Organic electroluminescent materials and devices

ABSTRACT

Provided are organometallic compounds having a structure of Formula I: 
     
       
         
         
             
             
         
       
     
     Also provided are formulations comprising these organometallic compounds. Further provided are OLEDs and related consumer products that utilize these organometallic compounds.

This application claims priority under 35 U.S.C. § 119(e) to U.S.Provisional Application No. 63/033,605, filed on Jun. 2, 2020, theentire contents of which are incorporated herein by reference.

FIELD

The present disclosure generally relates to organometallic compounds andformulations and their various uses including as emitters in devicessuch as organic light emitting diodes and related electronic devices.

BACKGROUND

Opto-electronic devices that make use of organic materials are becomingincreasingly desirable for various reasons. Many of the materials usedto make such devices are relatively inexpensive, so organicopto-electronic devices have the potential for cost advantages overinorganic devices. In addition, the inherent properties of organicmaterials, such as their flexibility, may make them well suited forparticular applications such as fabrication on a flexible substrate.Examples of organic opto-electronic devices include organic lightemitting diodes/devices (OLEDs), organic phototransistors, organicphotovoltaic cells, and organic photodetectors. For OLEDs, the organicmaterials may have performance advantages over conventional materials.

OLEDs make use of thin organic films that emit light when voltage isapplied across the device. OLEDs are becoming an increasinglyinteresting technology for use in applications such as flat paneldisplays, illumination, and backlighting.

One application for phosphorescent emissive molecules is a full colordisplay. Industry standards for such a display call for pixels adaptedto emit particular colors, referred to as “saturated” colors. Inparticular, these standards call for saturated red, green, and bluepixels. Alternatively, the OLED can be designed to emit white light. Inconventional liquid crystal displays emission from a white backlight isfiltered using absorption filters to produce red, green and blueemission. The same technique can also be used with OLEDs. The white OLEDcan be either a single emissive layer (EML) device or a stack structure.Color may be measured using CIE coordinates, which are well known to theart.

SUMMARY

In one aspect, the present disclosure provides a compound of Formula I:

wherein M is Pt or Pd; rings A, B, C, and D are each independently 5- or6-membered aryl or heteroaryl rings; R^(A), R^(B), R^(C), and R^(D) eachindependently represents zero, mono, or up to maximum allowedsubstitutions to its associated ring; Z¹, Z², Z³ and Z⁴ are eachindependently C or N; L¹, L², L³, L⁴ are each independently a directbond, BR, BRR′, NR, PR, O, S, Se, C═O, S═O, SO₂, CR′R″, SiR′R″, GeR′R″,or combinations thereof; n is 0 or 1; each of R, R′, and R″ isindependently a hydrogen or a substituent selected from the groupconsisting of the general substituents defined herein; each of R^(A),R^(B), R^(C), and R^(D) is independently a hydrogen, or a substituentselected from the group consisting of the general substituents definedherein, with at least one of R^(A), R^(B), R^(C), and R^(D) comprising astructure of Formula II or Formula III:

wherein X¹-X²⁴ are each independently C or N; each of R^(E)-R^(J) hasthe same definition as that of R^(A), R^(B), R^(C), or R^(D); themaximum number of N atoms that can connect with each other is two;

represents a single bond or a double bond; and any two adjacent R^(A),R^(B), R^(C), R^(D), R, R′, R″ substituents can be joined to form aring, with a proviso that none of rings A, B, C, and D is anN-heterocyclic carbene ligand.

In another aspect, the present disclosure provides a formulation of acompound of Formula I as described herein.

In yet another aspect, the present disclosure provides an OLED having anorganic layer comprising a compound of Formula I as described herein.

In yet another aspect, the present disclosure provides a consumerproduct comprising an OLED with an organic layer comprising a compoundof Formula I as described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an organic light emitting device.

FIG. 2 shows an inverted organic light emitting device that does nothave a separate electron transport layer.

DETAILED DESCRIPTION A. Terminology

Unless otherwise specified, the below terms used herein are defined asfollows:

As used herein, the term “organic” includes polymeric materials as wellas small molecule organic materials that may be used to fabricateorganic opto-electronic devices. “Small molecule” refers to any organicmaterial that is not a polymer, and “small molecules” may actually bequite large. Small molecules may include repeat units in somecircumstances. For example, using a long chain alkyl group as asubstituent does not remove a molecule from the “small molecule” class.Small molecules may also be incorporated into polymers, for example as apendent group on a polymer backbone or as a part of the backbone. Smallmolecules may also serve as the core moiety of a dendrimer, whichconsists of a series of chemical shells built on the core moiety. Thecore moiety of a dendrimer may be a fluorescent or phosphorescent smallmolecule emitter. A dendrimer may be a “small molecule,” and it isbelieved that all dendrimers currently used in the field of OLEDs aresmall molecules.

As used herein, “top” means furthest away from the substrate, while“bottom” means closest to the substrate. Where a first layer isdescribed as “disposed over” a second layer, the first layer is disposedfurther away from substrate. There may be other layers between the firstand second layer, unless it is specified that the first layer is “incontact with” the second layer. For example, a cathode may be describedas “disposed over” an anode, even though there are various organiclayers in between.

As used herein, “solution processable” means capable of being dissolved,dispersed, or transported in and/or deposited from a liquid medium,either in solution or suspension form.

A ligand may be referred to as “photoactive” when it is believed thatthe ligand directly contributes to the photoactive properties of anemissive material. A ligand may be referred to as “ancillary” when it isbelieved that the ligand does not contribute to the photoactiveproperties of an emissive material, although an ancillary ligand mayalter the properties of a photoactive ligand.

As used herein, and as would be generally understood by one skilled inthe art, a first “Highest Occupied Molecular Orbital” (HOMO) or “LowestUnoccupied Molecular Orbital” (LUMO) energy level is “greater than” or“higher than” a second HOMO or LUMO energy level if the first energylevel is closer to the vacuum energy level. Since ionization potentials(IP) are measured as a negative energy relative to a vacuum level, ahigher HOMO energy level corresponds to an IP having a smaller absolutevalue (an IP that is less negative). Similarly, a higher LUMO energylevel corresponds to an electron affinity (EA) having a smaller absolutevalue (an EA that is less negative). On a conventional energy leveldiagram, with the vacuum level at the top, the LUMO energy level of amaterial is higher than the HOMO energy level of the same material. A“higher” HOMO or LUMO energy level appears closer to the top of such adiagram than a “lower” HOMO or LUMO energy level.

As used herein, and as would be generally understood by one skilled inthe art, a first work function is “greater than” or “higher than” asecond work function if the first work function has a higher absolutevalue. Because work functions are generally measured as negative numbersrelative to vacuum level, this means that a “higher” work function ismore negative. On a conventional energy level diagram, with the vacuumlevel at the top, a “higher” work function is illustrated as furtheraway from the vacuum level in the downward direction. Thus, thedefinitions of HOMO and LUMO energy levels follow a different conventionthan work functions.

The terms “halo,” “halogen,” and “halide” are used interchangeably andrefer to fluorine, chlorine, bromine, and iodine.

The term “acyl” refers to a substituted carbonyl radical (C(O)—R_(s)).

The term “ester” refers to a substituted oxycarbonyl (—O—C(O)—R_(s) or—C(O)—O—R_(s)) radical.

The term “ether” refers to an —OR_(s) radical.

The terms “sulfanyl” or “thio-ether” are used interchangeably and referto a —SR_(s) radical.

The term “selenyl” refers to a —SeR_(s) radical.

The term “sulfinyl” refers to a —S(O)—R_(s) radical.

The term “sulfonyl” refers to a —SO₂—R_(s) radical.

The term “phosphino” refers to a —P(R_(S))₃ radical, wherein each R_(s)can be same or different.

The term “silyl” refers to a —Si(R_(s))₃ radical, wherein each R_(s) canbe same or different.

The term “germyl” refers to a —Ge(R_(s))₃ radical, wherein each R_(s)can be same or different.

The term “boryl” refers to a —B(R_(S))₂ radical or its Lewis adduct—B(R_(S))₃ radical, wherein R_(s) can be same or different.

In each of the above, R_(s) can be hydrogen or a substituent selectedfrom the group consisting of deuterium, halogen, alkyl, cycloalkyl,heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl,alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, andcombination thereof. Preferred R_(s) is selected from the groupconsisting of alkyl, cycloalkyl, aryl, heteroaryl, and combinationthereof.

The term “alkyl” refers to and includes both straight and branched chainalkyl radicals. Preferred alkyl groups are those containing from one tofifteen carbon atoms and includes methyl, ethyl, propyl, 1-methylethyl,butyl, 1-methylpropyl, 2-methylpropyl, pentyl, 1-methylbutyl,2-methylbutyl, 3-methylbutyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl,2,2-dimethylpropyl, and the like. Additionally, the alkyl group may beoptionally substituted.

The term “cycloalkyl” refers to and includes monocyclic, polycyclic, andspiro alkyl radicals. Preferred cycloalkyl groups are those containing 3to 12 ring carbon atoms and includes cyclopropyl, cyclopentyl,cyclohexyl, bicyclo[3.1.1]heptyl, spiro[4.5]decyl, spiro[5.5]undecyl,adamantyl, and the like. Additionally, the cycloalkyl group may beoptionally substituted.

The terms “heteroalkyl” or “heterocycloalkyl” refer to an alkyl or acycloalkyl radical, respectively, having at least one carbon atomreplaced by a heteroatom. Optionally the at least one heteroatom isselected from O, S, N, P, B, Si and Se, preferably, O, S or N.Additionally, the heteroalkyl or heterocycloalkyl group may beoptionally substituted.

The term “alkenyl” refers to and includes both straight and branchedchain alkene radicals. Alkenyl groups are essentially alkyl groups thatinclude at least one carbon-carbon double bond in the alkyl chain.Cycloalkenyl groups are essentially cycloalkyl groups that include atleast one carbon-carbon double bond in the cycloalkyl ring. The term“heteroalkenyl” as used herein refers to an alkenyl radical having atleast one carbon atom replaced by a heteroatom. Optionally the at leastone heteroatom is selected from O, S, N, P, B, Si, and Se, preferably,O, S, or N. Preferred alkenyl, cycloalkenyl, or heteroalkenyl groups arethose containing two to fifteen carbon atoms. Additionally, the alkenyl,cycloalkenyl, or heteroalkenyl group may be optionally substituted.

The term “alkynyl” refers to and includes both straight and branchedchain alkyne radicals. Alkynyl groups are essentially alkyl groups thatinclude at least one carbon-carbon triple bond in the alkyl chain.Preferred alkynyl groups are those containing two to fifteen carbonatoms. Additionally, the alkynyl group may be optionally substituted.

The terms “aralkyl” or “arylalkyl” are used interchangeably and refer toan alkyl group that is substituted with an aryl group. Additionally, thearalkyl group may be optionally substituted.

The term “heterocyclic group” refers to and includes aromatic andnon-aromatic cyclic radicals containing at least one heteroatom.Optionally the at least one heteroatom is selected from O, S, N, P, B,Si, and Se, preferably, O, S, or N. Hetero-aromatic cyclic radicals maybe used interchangeably with heteroaryl. Preferred hetero-non-aromaticcyclic groups are those containing 3 to 7 ring atoms which includes atleast one hetero atom, and includes cyclic amines such as morpholino,piperidino, pyrrolidino, and the like, and cyclic ethers/thio-ethers,such as tetrahydrofuran, tetrahydropyran, tetrahydrothiophene, and thelike. Additionally, the heterocyclic group may be optionallysubstituted.

The term “aryl” refers to and includes both single-ring aromatichydrocarbyl groups and polycyclic aromatic ring systems. The polycyclicrings may have two or more rings in which two carbons are common to twoadjoining rings (the rings are “fused”) wherein at least one of therings is an aromatic hydrocarbyl group, e.g., the other rings can becycloalkyls, cycloalkenyls, aryl, heterocycles, and/or heteroaryls.Preferred aryl groups are those containing six to thirty carbon atoms,preferably six to twenty carbon atoms, more preferably six to twelvecarbon atoms. Especially preferred is an aryl group having six carbons,ten carbons or twelve carbons. Suitable aryl groups include phenyl,biphenyl, triphenyl, triphenylene, tetraphenylene, naphthalene,anthracene, phenalene, phenanthrene, fluorene, pyrene, chrysene,perylene, and azulene, preferably phenyl, biphenyl, triphenyl,triphenylene, fluorene, and naphthalene. Additionally, the aryl groupmay be optionally substituted.

The term “heteroaryl” refers to and includes both single-ring aromaticgroups and polycyclic aromatic ring systems that include at least oneheteroatom. The heteroatoms include, but are not limited to O, S, N, P,B, Si, and Se. In many instances, O, S, or N are the preferredheteroatoms. Hetero-single ring aromatic systems are preferably singlerings with 5 or 6 ring atoms, and the ring can have from one to sixheteroatoms. The hetero-poly cyclic ring systems can have two or morerings in which two atoms are common to two adjoining rings (the ringsare “fused”) wherein at least one of the rings is a heteroaryl, e.g.,the other rings can be cycloalkyls, cycloalkenyls, aryl, heterocycles,and/or heteroaryls. The hetero-polycyclic aromatic ring systems can havefrom one to six heteroatoms per ring of the polycyclic aromatic ringsystem. Preferred heteroaryl groups are those containing three to thirtycarbon atoms, preferably three to twenty carbon atoms, more preferablythree to twelve carbon atoms. Suitable heteroaryl groups includedibenzothiophene, dibenzofuran, dibenzoselenophene, furan, thiophene,benzofuran, benzothiophene, benzoselenophene, carbazole,indolocarbazole, pyridylindole, pyrrolodipyridine, pyrazole, imidazole,triazole, oxazole, thiazole, oxadiazole, oxatriazole, dioxazole,thiadiazole, pyridine, pyridazine, pyrimidine, pyrazine, triazine,oxazine, oxathiazine, oxadiazine, indole, benzimidazole, indazole,indoxazine, benzoxazole, benzisoxazole, benzothiazole, quinoline,isoquinoline, cinnoline, quinazoline, quinoxaline, naphthyridine,phthalazine, pteridine, xanthene, acridine, phenazine, phenothiazine,phenoxazine, benzofuropyridine, furodipyridine, benzothienopyridine,thienodipyridine, benzoselenophenopyridine, and selenophenodipyridine,preferably dibenzothiophene, dibenzofuran, dibenzoselenophene,carbazole, indolocarbazole, imidazole, pyridine, triazine,benzimidazole, 1,2-azaborine, 1,3-azaborine, 1,4-azaborine, borazine,and aza-analogs thereof. Additionally, the heteroaryl group may beoptionally substituted.

Of the aryl and heteroaryl groups listed above, the groups oftriphenylene, naphthalene, anthracene, dibenzothiophene, dibenzofuran,dibenzoselenophene, carbazole, indolocarbazole, imidazole, pyridine,pyrazine, pyrimidine, triazine, and benzimidazole, and the respectiveaza-analogs of each thereof are of particular interest.

The terms alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, alkenyl,cycloalkenyl, heteroalkenyl, alkynyl, aralkyl, heterocyclic group, aryl,and heteroaryl, as used herein, are independently unsubstituted, orindependently substituted, with one or more general substituents.

In many instances, the general substituents are selected from the groupconsisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl,heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, germyl,boryl, selenyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl,heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile,sulfanyl, sulfinyl, sulfonyl, phosphino, selenyl, and combinationsthereof.

In some instances, the preferred general substituents are selected fromthe group consisting of deuterium, fluorine, alkyl, cycloalkyl,heteroalkyl, alkoxy, aryloxy, amino, silyl, boryl, alkenyl,cycloalkenyl, heteroalkenyl, aryl, heteroaryl, nitrile, isonitrile,sulfanyl, and combinations thereof.

In some instances, the preferred general substituents are selected fromthe group consisting of deuterium, fluorine, alkyl, cycloalkyl, alkoxy,aryloxy, amino, silyl, boryl, aryl, heteroaryl, sulfanyl, andcombinations thereof.

In yet other instances, the more preferred general substituents areselected from the group consisting of deuterium, fluorine, alkyl,cycloalkyl, aryl, heteroaryl, and combinations thereof.

The terms “substituted” and “substitution” refer to a substituent otherthan H that is bonded to the relevant position, e.g., a carbon ornitrogen. For example, when R¹ represents mono-substitution, then one R¹must be other than H (i.e., a substitution). Similarly, when R¹represents di-substitution, then two of R¹ must be other than H.Similarly, when R¹ represents zero or no substitution, R¹, for example,can be a hydrogen for available valencies of ring atoms, as in carbonatoms for benzene and the nitrogen atom in pyrrole, or simply representsnothing for ring atoms with fully filled valencies, e.g., the nitrogenatom in pyridine. The maximum number of substitutions possible in a ringstructure will depend on the total number of available valencies in thering atoms.

As used herein, “combinations thereof” indicates that one or moremembers of the applicable list are combined to form a known orchemically stable arrangement that one of ordinary skill in the art canenvision from the applicable list. For example, an alkyl and deuteriumcan be combined to form a partial or fully deuterated alkyl group; ahalogen and alkyl can be combined to form a halogenated alkylsubstituent; and a halogen, alkyl, and aryl can be combined to form ahalogenated arylalkyl. In one instance, the term substitution includes acombination of two to four of the listed groups. In another instance,the term substitution includes a combination of two to three groups. Inyet another instance, the term substitution includes a combination oftwo groups. Preferred combinations of substituent groups are those thatcontain up to fifty atoms that are not hydrogen or deuterium, or thosewhich include up to forty atoms that are not hydrogen or deuterium, orthose that include up to thirty atoms that are not hydrogen ordeuterium. In many instances, a preferred combination of substituentgroups will include up to twenty atoms that are not hydrogen ordeuterium.

The “aza” designation in the fragments described herein, i.e.aza-dibenzofuran, aza-dibenzothiophene, etc. means that one or more ofthe C—H groups in the respective aromatic ring can be replaced by anitrogen atom, for example, and without any limitation, azatriphenyleneencompasses both dibenzo[f,h]quinoxaline and dibenzo[f,h]quinoline. Oneof ordinary skill in the art can readily envision other nitrogen analogsof the aza-derivatives described above, and all such analogs areintended to be encompassed by the terms as set forth herein.

As used herein, “deuterium” refers to an isotope of hydrogen. Deuteratedcompounds can be readily prepared using methods known in the art. Forexample, U.S. Pat. No. 8,557,400, Patent Pub. No. WO 2006/095951, andU.S. Pat. Application Pub. No. US 2011/0037057, which are herebyincorporated by reference in their entireties, describe the making ofdeuterium-substituted organometallic complexes. Further reference ismade to Ming Yan, el al., Tetrahedron 2015, 71, 1425-30 and Atzrodt etal., Angew. Chem. Int. Ed. (Reviews) 2007, 46, 7744-65, which areincorporated by reference in their entireties, describe the deuterationof the methylene hydrogens in benzyl amines and efficient pathways toreplace aromatic ring hydrogens with deuterium, respectively.

It is to be understood that when a molecular fragment is described asbeing a substituent or otherwise attached to another moiety, its namemay be written as if it were a fragment (e.g. phenyl, phenylene,naphthyl, dibenzofuryl) or as if it were the whole molecule (e.g.benzene, naphthalene, dibenzofuran). As used herein, these differentways of designating a substituent or attached fragment are considered tobe equivalent.

In some instance, a pair of adjacent substituents can be optionallyjoined or fused into a ring. The preferred ring is a five, six, orseven-membered carbocyclic or heterocyclic ring, includes both instanceswhere the portion of the ring formed by the pair of substituents issaturated and where the portion of the ring formed by the pair ofsubstituents is unsaturated. As used herein, “adjacent” means that thetwo substituents involved can be on the same ring next to each other, oron two neighboring rings having the two closest available substitutablepositions, such as 2, 2′ positions in a biphenyl, or 1, 8 position in anaphthalene, as long as they can form a stable fused ring system.

B. The Compounds of the Present Disclosure

In one aspect, the present disclosure provides a compound of Formula I:

wherein: M is Pt or Pd; rings A, B, C, and D are each independently 5-or 6-membered aryl or heteroaryl rings; R^(A), R^(B), R^(C), and R^(D)each independently represent zero, mono, or up to maximum allowedsubstitutions to its associated ring; Z¹, Z², Z³ and Z⁴ are eachindependently C or N; L¹, L², L³, L⁴ are each independently a directbond, BR, BRR′, NR, PR, O, S, Se, C═O, S═O, SO₂, CR′R″, SiR′R″, GeR′R″,or combinations thereof; n is 0 (L⁴ not present) or 1; each of R, R′,and R″ is independently a hydrogen or a substituent selected from thegroup consisting of the general substituents defined herein; each ofR^(A), R^(B), R^(C), and R^(D) is independently a hydrogen, or asubstituent selected from the group consisting of the generalsubstituents defined herein, with at least one of R^(A), R^(B), R^(C),and R^(D) comprising a structure of Formula II or Formula III:

X¹-X²⁴ are each independently C or N;each of R^(E)-R^(J) has the same definition as that of R^(A), R^(B),R^(C), or R^(D);the maximum number of N atoms that can connect with each other is two;

represents a single bond or a double bond; andany two adjacent R^(A), R^(B), R^(C), R^(D), R, R′, R″ substituents canbe joined to form a ring,with a proviso that none of rings A, B, C, and D is an N-heterocycliccarbene ligand.

It should be understood that when two adjacent R^(A) substituents,and/or two adjacent R^(B) substituents, and/or two adjacent R^(C)substituents, and/or two adjacent R^(D) substituents, and/or any twoadjacent substituents are joined to form a ring, Formula II or FormulaIII can also be attached to the newly formed ring. Similarly, when thering is further extended to form a multiring structure, Formula II orFormula III can also be attached to any ring of the extended ringstructure.

In some embodiments, each of R^(A), R^(B), R^(C), R^(D), R^(E), R^(F),R^(G), R^(H), R^(I), R^(J), R, R′, and R″ can be independently ahydrogen or a substituent selected from the group consisting ofdeuterium, fluorine, alkyl, cycloalkyl, heteroalkyl, alkoxy, aryloxy,amino, silyl, boryl, alkenyl, cycloalkenyl, heteroalkenyl, aryl,heteroaryl, nitrile, isonitrile, sulfanyl, and combinations thereof.

In some embodiments, when n=0, it means L⁴ is not present. In someembodiments, X¹-X⁵ can be each C. In some embodiments, X⁶-X⁸ can be eachC. In some embodiments, X⁹-X¹³ can be each C. In some embodiments,X¹-X¹¹ can be each C. In some embodiments, at least one of X¹-X¹³ can beN. In some embodiments, X¹⁷-X¹⁹ can be each C. In some embodiments, atleast one of X¹⁷-X¹⁹ can be N. In some embodiments, X²⁰-X²⁴ can be eachC. In some embodiments, at least one X²⁰-X²⁴ can be N. In someembodiments, X¹⁴ can be N and X¹⁵ and X¹⁶ can be both C. In someembodiments, X¹⁴-X¹⁵ can be a single bond, and X¹⁵-X¹⁶ can be a doublebond. In some embodiments, X¹⁴ and X¹⁶ can be both N, and X¹⁵ can be C.In some embodiments, X¹⁴-X¹⁵ can be a single bond, X¹⁵-X¹⁶ can be asingle bond. In some embodiments, Z¹ and Z⁴ can be both N, and Z² and Z³can be both C. In some embodiments, Z¹ and Z⁴ can be both C, and Z² andZ³ can be both N.

In some embodiments, rings A, B, C, and D can be all 6-membered aromaticrings. In some embodiments, three of rings A, B, C, and D can be6-membered aromatic rings, and the remaining one can be a 5-memberedaromatic ring. In some embodiments, rings A, B, and C can be 6-memberedaromatic rings, and ring D can be a 5-membered aromatic ring. In someembodiments, two of rings A, B, C, and D can be 5-membered aromaticrings, and the remaining two can be 6-membered aromatic rings. In someembodiments, rings A and D can be 5-membered aromatic rings, and rings Band C can be 6-membered aromatic rings. In some embodiments, rings A andC can be 6-membered aromatic rings, and rings B and D can be 5-memberedaromatic rings. In some embodiments, three of rings A, B, C, and D canbe 5-membered aromatic rings, and the remaining one can be a pyridine.

In some embodiments, L¹, L², and L³ can each be independently selectedfrom the group consisting of a direct bond, NR, BR, BRR′, O, S, CR′R″,SiR′R″, and combinations thereof, while L⁴ is not present. In someembodiments, L² can be O. In some embodiments, L¹ and L³ can be bothdirect bonds. In some embodiments, one of L¹ and L³ can be a directbond, and L² can be NR.

In some embodiments, two adjacent R^(A) substituents can be fused toform a 5- or 6-membered ring. In some embodiments, two adjacent R^(B)substituents can be fused to form a 5- or 6-membered ring. In someembodiments, two adjacent R^(C) substituents can be fused to form a 5-or 6-membered ring. In some embodiments, two adjacent R^(D) substituentscan be fused to form a 5- or 6-membered ring. In some embodiments, oneL¹ substituent when present and one R^(B) substituent can be joined toform a 5- or 6-membered ring fused to ring B. In some embodiments, twoadjacent R¹ substituents can be fused to form a 5- or 6-membered ring.In some embodiments, one of R^(A) can comprise Formula II or FormulaIII. In some embodiments, one of R^(D) can comprise Formula II orFormula III.

In some embodiments, ring A, ring B, ring C, and ring D can be eachindependently selected from pyridine, benzene, pyrazine, pyrimidine,triazine, pyrrole, imidazole, thiophene, furan, thiazole, pyrazole andoxazole. In some embodiments, ring A, ring B, ring C, and ring D can beeach independently pyridine or benzene.

In some embodiments, M can be Pt.

In some embodiments, the compound can be selected from the groupconsisting of:

-   -   wherein Q¹-Q¹⁴ are each independently C or N; and the remaining        variables are the same as previously defined.

In some embodiments, the compound can be selected from the groupconsisting of:

wherein: R^(x) and R^(y) are each selected from the group consisting ofalkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, aryl, heteroaryl, andcombinations thereof;R^(E) for each occurrence is independently a hydrogen or a substituentselected from the group consisting of deuterium, fluorine, alkyl,cycloalkyl, heteroalkyl, alkoxy, aryloxy, amino, silyl, boryl, alkenyl,cycloalkenyl, heteroalkenyl, aryl, heteroaryl, nitrile, isonitrile,sulfanyl, and combinations thereof; andR^(A), R^(B), R^(C), R^(D), R^(E), L², L³, ring C, and ring D are allthe same as previously defined.

In some embodiments, the compound can be selected from the groupconsisting of Compound of the formula T_(n-j) wherein n is an integerfrom 1 to 116 and j is an integer from 1 to 504, wherein the structureof each formula T_(n-j) is defined in Table 1 below:

TABLE 1 Structure Z¹ to Z⁴ for T₁ to T₅, the compound has wherein: thefollowing structure for T_(1-j): Z¹ and Z² = N, Z³

and Z⁴ = C; for T_(2-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(3-j): Z¹and Z⁴ = N, Z² and Z³ = C; for T_(4-j): Z² and Z³ = N, Z¹ and Z⁴ = C;and for T_(5-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₆ to T₁₀, thecompound wherein: has the following structure for T_(6-j): Z¹ and Z² =N, Z³

and Z⁴ = C; for T_(7-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(8-j): Z¹and Z⁴ = N, Z² and Z³ = C; for T_(9-j): Z² and Z³ = N, Z¹ and Z⁴ = C;and for T_(1-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₁₁ to T₁₅, thecompound wherein: has the following structure for T_(11-j): Z¹ and Z² =N, Z³

and Z⁴ = C; For T_(12-j): Z¹ and Z³ = N, Z² and Z⁴ = C; For T_(13-j): Z¹and Z⁴ = N, Z² and Z³ = C; For T_(14-j): Z² and Z³ = N, Z¹ and Z⁴ = C;and For T_(15-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₁₆ to T₂₀, thecompound wherein: has the following structure for T_(16-j): Z¹ and Z² =N, Z³

and Z⁴ = C; for T_(17-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(18-j): Z¹and Z⁴ = N, Z² and Z³ = C; for T_(19-j): Z² and Z³ = N, Z¹ and Z⁴ = C;and for T_(20-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₂₁ to T₂₅, thecompound wherein: has the following structure for T_(21-j): Z¹ and Z² =N, Z³

and Z⁴ = C; for T_(22-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(23-j): Z¹and Z⁴ = N, Z² and Z³ = C; for T_(24-j): Z² and Z³ = N, Z¹ and Z⁴ = C;and for T_(25-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₂₆ to T₃₀, thecompound wherein: has the following structure for T_(26-j): Z¹ and Z² =N, Z³

and Z⁴ = C; for T_(27-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(28-j): Z¹and Z⁴ = N, Z² and Z³ = C; for T_(29-j): Z² and Z³ = N, Z¹ and Z⁴ = C;and for T_(30-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₃₁ to T₃₅, thecompound wherein: has the following structure for T_(31-j): Z¹ and Z² =N, Z³

and Z⁴ = C; for T_(32-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(33-j): Z¹and Z⁴ = N, Z² and Z³ = C; for T_(34-j): Z² and Z³ = N, Z¹ and Z⁴ = C;and for T_(35-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₃₆ to T₄₀, thecompound wherein: has the following structure for T_(36-j): Z¹ and Z² =N, Z³

and Z⁴ = C; for T_(37-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(38-j): Z¹and Z⁴ = N, Z² and Z³ = C; for T_(39-j): Z² and Z³ = N, Z¹ and Z⁴ = C;and for T_(40-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₄₁ to T₄₅, thecompound for T_(41-j): Z¹ and Z² = N, Z³ has the following structure andZ⁴ = C;

for T_(42-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(43-j): Z¹ and Z⁴ = N,Z² and Z³ = C; for T_(44-j): Z² and Z³ = N, Z¹ and Z⁴ = C; and forT_(45-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₄₆ to T₅₀, the compound forT_(46-j): Z¹ and Z² = N, Z³ has the following structure and Z⁴ = C;

for T_(47-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(48-j): Z¹ and Z⁴ = N,Z² and Z³ = C; and for T_(50-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₅₁to T₅₆, the compound for T_(51-j): Z¹ and Z² = N, Z³ has the followingstructure and Z⁴ = C;

for T_(52-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(53-j): Z¹ and Z⁴ = N,Z² and Z³ = C; for T_(54-j): Z² and Z³ = N, Z¹ and Z⁴ = C; and forT_(55-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₅₆ to T₆₀, the compound forT_(56-j): Z¹ and Z² = N, Z³ has the following structure and Z⁴ = C;

for T_(57-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(58-j): Z¹ and Z⁴ = N,Z² and Z³ = C; for T_(59-j): Z² and Z³ = N, Z¹ and Z⁴ = C; and forT_(60-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₆₁ to T₆₅, the compound forT_(61-j): Z¹ and Z² = N, Z³ has the following structure and Z⁴ = C;

for T_(62-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(63-j): Z¹ and Z⁴ = N,Z² and Z³ = C; for T_(64-j): Z² and Z³ = N, Z¹ and Z⁴ = C; and forT_(65-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₆₆ to T₇₀, the compound forT_(66-j): Z¹ and Z² = N, Z³ has the following structure and Z⁴ = C;

for T_(67-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(68-j): Z¹ and Z⁴ = N,Z² and Z³ = C; for T_(69-j): Z² and Z³ = N, Z¹ and Z⁴ = C; and forT_(70-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₇₁ to T₇₅, the compound forT_(71-j): Z¹ and Z² = N, Z³ has the following structure and Z⁴ = C;

for T_(72-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(73-j): Z¹ and Z⁴ = N,Z² and Z³ = C; and for T_(74-j): Z² and Z³ = N, Z¹ and Z⁴ = C; and forT_(75-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₇₆ to T₈₀, the compound forT_(76-j): Z¹ and Z² = N, Z³ has the following structure and Z⁴ = C;

for T_(77-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(78-j): Z¹ and Z⁴ = N,Z² and Z³ = C; for T_(79-j): Z² and Z³ = N, Z¹ and Z⁴ = C; and forT_(80-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₈₁ to T₈₅, the compound forT_(81-j): Z¹ and Z² = N, Z³ has the following structure and Z⁴ = C;

for T_(82-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(83-j): Z¹ and Z⁴ = N,Z² and Z³ = C; for T_(84-j): Z² and Z³ = N, Z¹ and Z⁴ = C; and forT_(85-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₈₆ to T₉₀, the compound forT_(86-j): Z¹ and Z² = N, Z³ has the following structure and Z⁴ = C;

for T_(87-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(88-j): Z¹ and Z⁴ = N,Z² and Z³ = C; and for T_(89-j): Z² and Z³ = N, Z¹ and Z⁴ = C; and forT_(90-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₉₁ to T₉₅, the compound forT_(91-j): Z¹ and Z² = N, Z³ has the following structure and Z⁴ = C;

for T_(92-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(93-j): Z¹ and Z⁴ = N,Z² and Z³ = C; for T_(94-j): Z² and Z³ = N, Z¹ and Z⁴ = C; and forT_(95-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₉₆ to T₁₀₀, the compoundfor T_(96-j): Z¹ and Z² = N, Z³ has the following structure and Z⁴ = C;

for T_(97-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(98-j): Z¹ and Z⁴ = N,Z² and Z³ = C; for T_(99-j): Z² and Z³ = N, Z¹ and Z⁴ = C; and forT_(100-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₁₀₁ to T₁₀₅, the compoundfor T_(101-j): Z¹ and Z² = N, Z³ has the following structure and Z⁴ = C;

for T_(102-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(103-j): Z¹ and Z⁴ =N, Z² and Z³ = C; and for T_(104-j): Z² and Z³ = N, Z¹ and Z⁴ = C; andfor T_(105-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₁₀₆ to T₁₁₀, thecompound for T_(106-j): Z¹ and Z² = N, Z³ has the following structureand Z⁴ = C;

for T_(107-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(108-j): Z¹ and Z⁴ =N, Z² and Z³ = C; for T_(109-j): Z² and Z³ = N, Z¹ and Z⁴ = C; and forT_(110-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₁₁₁ to T₁₁₃, the compoundfor T_(111-j): Z¹ and Z³ = N, has the following structure Z⁴ = C;

for T_(112-j): Z¹ and Z⁴ = N, Z³ = C; and for T_(113-j): Z³ and Z⁴ = N,Z¹ = C; for T₁₁₄ to T₁₁₆, the compound for T_(114-j): Z¹ and Z³ = N, hasthe following structure Z⁴ = C;

for T_(115-j): Z¹ and Z⁴ = N, Z³ = C; and for T_(116-j): Z³ and Z⁴ = N,Z¹ = C; for T₁₁₇ to T₁₁₉, the compound for T_(117-j): Z¹ and Z³ = N, hasthe following structure Z⁴ = C;

for T_(118-j): Z¹ Z⁴ = N, Z³ = C; and for T_(119-j): Z³ and Z⁴ = N, Z¹ =C; for T₁₂₀ to T₁₂₂, the compound for T_(120-j): Z¹ and Z³ = N, has thefollowing structure Z⁴ = C;

for T_(121-j): Z¹ and Z⁴ = N, Z³ = C; and for T_(122-j): Z³ and Z⁴ = N,Z¹ = C; for T123 to T₁₂₇, the compound for T_(123-j): Z¹ and Z² = N, Z³has the following structure and Z⁴ = C;

for T_(124-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(125-j): Z¹ and Z⁴ =N, Z² and Z³ = C; for T_(126-j): Z² and Z³ = N, Z¹ and Z⁴ = C; and forT_(127-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₁₂₈ to T₁₃₂, the compoundfor T_(128-j): Z¹ and Z² = N, Z³ has the following structure and Z⁴ = C;

for T_(129-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(130-j): Z¹ and Z⁴ =N, Z² and Z³ = C; for T_(131-j): Z² and Z³ = N, Z¹ and Z⁴ = C; and forT_(132-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₁₃₃ to T₁₃₇, the compoundfor T_(133-j): Z¹ and Z² = N, Z³ has the following structure and Z⁴ = C;

for T_(134-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(135-j): Z¹ and Z⁴ =N, Z² and Z³ = C; for T_(136-j): Z² and Z³ = N, Z¹ and Z⁴ = C; and forT_(137-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₁₃₈ to T₁₄₂, the compoundfor T_(138-j): Z¹ and Z² = N, Z³ has the following structure and Z⁴ = C;

for T_(139-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(140-j): Z¹ and Z⁴ =N, Z² and Z³ = C; for T_(141-j): Z² and Z³ = N, Z¹ and Z⁴ = C; and forT_(142-j): Z³ and Z⁴ = N, Z¹ and Z² = C;

-   -   wherein, for each j, the substituents A, R¹, R², R³, R⁴, R⁵, R⁶,        and R⁷ are defined as follows:

j A R¹ R² R³ R⁴ R⁵ R⁶ R⁷ 1. A1 H H H H H H H 2. A2 H H H H H H H 3. A3 HH H H H H H 4. A4 H H H H H H H 5. A5 H H H H H H H 6. A6 H H H H H H H7. A7 H H H H H H H 8. A8 H H H H H H H 9. A9 H H H H H H H 10. A10 H HH H H H H 11. A11 H H H H H H H 12. A12 H H H H H H H 13. A13 H H H H HH H 14. A14 H H H H H H H 15. A15 H H H H H H H 16. A16 H H H H H H H17. A17 H H H H H H H 18. A18 H H H H H H H 19. A19 H H H H H H H 20.A20 H H H H H H H 21. A21 H H H H H H H 22. A22 H H H H H H H 23. A23 HH H H H H H 24. A24 H H H H H H H 25. A25 H H H H H H H 26. A26 H H H HH H H 27. A27 H H H H H H H 28. A28 H H H H H H H 29. A1 Me H H H H H H30. A2 Me H H H H H H 31. A3 Me H H H H H H 32. A4 Me H H H H H H 33. A5Me H H H H H H 34. A6 Me H H H H H H 35. A7 Me H H H H H H 36. A8 Me H HH H H H 37. A9 Me H H H H H H 38. A10 Me H H H H H H 39. A11 Me H H H HH H 40. A12 Me H H H H H H 41. A13 Me H H H H H H 42. A14 Me H H H H H H43. A15 Me H H H H H H 44. A16 Me H H H H H H 45. A17 Me H H H H H H 46.A18 Me H H H H H H 47. A19 Me H H H H H H 48. A20 Me H H H H H H 49. A21Me H H H H H H 50. A22 Me H H H H H H 51. A23 Me H H H H H H 52. A24 MeH H H H H H 53. A25 Me H H H H H H 54. A26 Me H H H H H H 55. A27 Me H HH H H H 56. A28 Me H H H H H H 57. A1 tert-Bu H H H H H H 58. A2 tert-BuH H H H H H 59. A3 tert-Bu H H H H H H 60. A4 tert-Bu H H H H H H 61. A5tert-Bu H H H H H H 62. A6 tert-Bu H H H H H H 63. A7 tert-Bu H H H H HH 64. A8 tert-Bu H H H H H H 65. A9 tert-Bu H H H H H H 66. A10 tert-BuH H H H H H 67. A11 tert-Bu H H H H H H 68. A12 tert-Bu H H H H H H 69.A13 tert-Bu H H H H H H 70. A14 tert-Bu H H H H H H 71. A15 tert-Bu H HH H H H 72. A16 tert-Bu H H H H H H 73. A17 tert-Bu H H H H H H 74. A18tert-Bu H H H H H H 75. A19 tert-Bu H H H H H H 76. A20 tert-Bu H H H HH H 77. A21 tert-Bu H H H H H H 78. A22 tert-Bu H H H H H H 79. A23tert-Bu H H H H H H 80. A24 tert-Bu H H H H H H 81. A25 tert-Bu H H H HH H 82. A26 tert-Bu H H H H H H 83. A27 tert-Bu H H H H H H 84. A28tert-Bu H H H H H H 85. A1 H Me H H H H H 86. A2 H Me H H H H H 87. A3 HMe H H H H H 88. A4 H Me H H H H H 89. A5 H Me H H H H H 90. A6 H Me H HH H H 91. A7 H Me H H H H H 92. A8 H Me H H H H H 93. A9 H Me H H H H H94. A10 H Me H H H H H 95. A11 H Me H H H H H 96. A12 H Me H H H H H 97.A13 H Me H H H H H 98. A14 H Me H H H H H 99. A15 H Me H H H H H 100.A16 H Me H H H H H 101. A17 H Me H H H H H 102. A18 H Me H H H H H 103.A19 H Me H H H H H 104. A20 H Me H H H H H 105. A21 H Me H H H H H 106.A22 H Me H H H H H 107. A23 H Me H H H H H 108. A24 H Me H H H H H 109.A25 H Me H H H H H 110. A26 H Me H H H H H 111. A27 H Me H H H H H 112.A28 H Me H H H H H 113. A1 H tert-Bu H H H H H 114. A2 H tert-Bu H H H HH 115. A3 H tert-Bu H H H H H 116. A4 H tert-Bu H H H H H 117. A5 Htert-Bu H H H H H 118. A6 H tert-Bu H H H H H 119. A7 H tert-Bu H H H HH 120. A8 H tert-Bu H H H H H 121. A9 H tert-Bu H H H H H 122. A10 Htert-Bu H H H H H 123. A11 H tert-Bu H H H H H 124. A12 H tert-Bu H H HH H 125. A13 H tert-Bu H H H H H 126. A14 H tert-Bu H H H H H 127. A15 Htert-Bu H H H H H 128. A16 H tert-Bu H H H H H 129. A17 H tert-Bu H H HH H 130. A18 H tert-Bu H H H H H 131. A19 H tert-Bu H H H H H 132. A20 Htert-Bu H H H H H 133. A21 H tert-Bu H H H H H 134. A22 H tert-Bu H H HH H 135. A23 H tert-Bu H H H H H 136. A24 H tert-Bu H H H H H 137. A25 Htert-Bu H H H H H 138. A26 H tert-Bu H H H H H 139. A27 H tert-Bu H H HH H 140. A28 H tert-Bu H H H H H 141. A1 H H Me H H H H 142. A2 H H Me HH H H 143. A3 H H Me H H H H 144. A4 H H Me H H H H 145. A5 H H Me H H HH 146. A6 H H Me H H H H 147. A7 H H Me H H H H 148. A8 H H Me H H H H149. A9 H H Me H H H H 150. A10 H H Me H H H H 151. A11 H H Me H H H H152. A12 H H Me H H H H 153. A13 H H Me H H H H 154. A14 H H Me H H H H155. A15 H H Me H H H H 156. A16 H H Me H H H H 157. A17 H H Me H H H H158. A18 H H Me H H H H 159. A19 H H Me H H H H 160. A20 H H Me H H H H161. A21 H H Me H H H H 162. A22 H H Me H H H H 163. A23 H H Me H H H H164. A24 H H Me H H H H 165. A25 H H Me H H H H 166. A26 H H Me H H H H167. A27 H H Me H H H H 168. A28 H H Me H H H H 169. A1 H H tert-Bu H HH H 170. A2 H H tert-Bu H H H H 171. A3 H H tert-Bu H H H H 172. A4 H Htert-Bu H H H H 173. A5 H H tert-Bu H H H H 174. A6 H H tert-Bu H H H H175. A7 H H tert-Bu H H H H 176. A8 H H tert-Bu H H H H 177. A9 H Htert-Bu H H H H 178. A10 H H tert-Bu H H H H 179. A11 H H tert-Bu H H HH 180. A12 H H tert-Bu H H H H 181. A13 H H tert-Bu H H H H 182. A14 H Htert-Bu H H H H 183. A15 H H tert-Bu H H H H 184. A16 H H tert-Bu H H HH 185. A17 H H tert-Bu H H H H 186. A18 H H tert-Bu H H H H 187. A19 H Htert-Bu H H H H 188. A20 H H tert-Bu H H H H 189. A21 H H tert-Bu H H HH 190. A22 H H tert-Bu H H H H 191. A23 H H tert-Bu H H H H 192. A24 H Htert-Bu H H H H 193. A25 H H tert-Bu H H H H 194. A26 H H tert-Bu H H HH 195. A27 H H tert-Bu H H H H 196. A28 H H tert-Bu H H H H 197. A1 H HH Me H H H 198. A2 H H H Me H H H 199. A3 H H H Me H H H 200. A4 H H HMe H H H 201. A5 H H H Me H H H 202. A6 H H H Me H H H 203. A7 H H H MeH H H 204. A8 H H H Me H H H 205. A9 H H H Me H H H 206. A10 H H H Me HH H 207. A11 H H H Me H H H 208. A12 H H H Me H H H 209. A13 H H H Me HH H 210. A14 H H H Me H H H 211. A15 H H H Me H H H 212. A16 H H H Me HH H 213. A17 H H H Me H H H 214. A18 H H H Me H H H 215. A19 H H H Me HH H 216. A20 H H H Me H H H 217. A21 H H H Me H H H 218. A22 H H H Me HH H 219. A23 H H H Me H H H 220. A24 H H H Me H H H 221. A25 H H H Me HH H 222. A26 H H H Me H H H 223. A27 H H H Me H H H 224. A28 H H H Me HH H 225. A1 H H H tert-Bu H H H 226. A2 H H H tert-Bu H H H 227. A3 H HH tert-Bu H H H 228. A4 H H H tert-Bu H H H 229. A5 H H H tert-Bu H H H230. A6 H H H tert-Bu H H H 231. A7 H H H tert-Bu H H H 232. A8 H H Htert-Bu H H H 233. A9 H H H tert-Bu H H H 234. A10 H H H tert-Bu H H H235. A11 H H H tert-Bu H H H 236. A12 H H H tert-Bu H H H 237. A13 H H Htert-Bu H H H 238. A14 H H H tert-Bu H H H 239. A15 H H H tert-Bu H H H240. A16 H H H tert-Bu H H H 241. A17 H H H tert-Bu H H H 242. A18 H H Htert-Bu H H H 243. A19 H H H tert-Bu H H H 244. A20 H H H tert-Bu H H H245. A21 H H H tert-Bu H H H 246. A22 H H H tert-Bu H H H 247. A23 H H Htert-Bu H H H 248. A24 H H H tert-Bu H H H 249. A25 H H H tert-Bu H H H250. A26 H H H tert-Bu H H H 251. A27 H H H tert-Bu H H H 252. A28 H H Htert-Bu H H H 253. A1 H H H H Me H H 254. A2 H H H H Me H H 255. A3 H HH H Me H H 256. A4 H H H H Me H H 257. A5 H H H H Me H H 258. A6 H H H HMe H H 259. A7 H H H H Me H H 260. A8 H H H H Me H H 261. A9 H H H H MeH H 262. A10 H H H H Me H H 263. A11 H H H H Me H H 264. A12 H H H H MeH H 265. A13 H H H H Me H H 266. A14 H H H H Me H H 267. A15 H H H H MeH H 268. A16 H H H H Me H H 269. A17 H H H H Me H H 270. A18 H H H H MeH H 271. A19 H H H H Me H H 272. A20 H H H H Me H H 273. A21 H H H H MeH H 274. A22 H H H H Me H H 275. A23 H H H H Me H H 276. A24 H H H H MeH H 277. A25 H H H H Me H H 278. A26 H H H H Me H H 279. A27 H H H H MeH H 280. A28 H H H H Me H H 281. A1 H H H H tert-Bu H H 282. A2 H H H Htert-Bu H H 283. A3 H H H H tert-Bu H H 284. A4 H H H H tert-Bu H H 285.A5 H H H H tert-Bu H H 286. A6 H H H H tert-Bu H H 287. A7 H H H Htert-Bu H H 288. A8 H H H H tert-Bu H H 289. A9 H H H H tert-Bu H H 290.A10 H H H H tert-Bu H H 291. A11 H H H H tert-Bu H H 292. A12 H H H Htert-Bu H H 293. A13 H H H H tert-Bu H H 294. A14 H H H H tert-Bu H H295. A15 H H H H tert-Bu H H 296. A16 H H H H tert-Bu H H 297. A17 H H HH tert-Bu H H 298. A18 H H H H tert-Bu H H 299. A19 H H H H tert-Bu H H300. A20 H H H H tert-Bu H H 301. A21 H H H H tert-Bu H H 302. A22 H H HH tert-Bu H H 303. A23 H H H H tert-Bu H H 304. A24 H H H H tert-Bu H H305. A25 H H H H tert-Bu H H 306. A26 H H H H tert-Bu H H 307. A27 H H HH tert-Bu H H 308. A28 H H H H tert-Bu H H 309. A1 H H H H H Me H 310.A2 H H H H H Me H 311. A3 H H H H H Me H 312. A4 H H H H H Me H 313. A5H H H H H Me H 314. A6 H H H H H Me H 315. A7 H H H H H Me H 316. A8 H HH H H Me H 317. A9 H H H H H Me H 318. A10 H H H H H Me H 319. A11 H H HH H Me H 320. A12 H H H H H Me H 321. A13 H H H H H Me H 322. A14 H H HH H Me H 323. A15 H H H H H Me H 324. A16 H H H H H Me H 325. A17 H H HH H Me H 326. A18 H H H H H Me H 327. A19 H H H H H Me H 328. A20 H H HH H Me H 329. A21 H H H H H Me H 330. A22 H H H H H Me H 331. A23 H H HH H Me H 332. A24 H H H H H Me H 333. A25 H H H H H Me H 334. A26 H H HH H Me H 335. A27 H H H H H Me H 336. A28 H H H H H Me H 337. A1 H H H HH tert-Bu H 338. A2 H H H H H tert-Bu H 339. A3 H H H H H tert-Bu H 340.A4 H H H H H tert-Bu H 341. A5 H H H H H tert-Bu H 342. A6 H H H H Htert-Bu H 343. A7 H H H H H tert-Bu H 344. A8 H H H H H tert-Bu H 345.A9 H H H H H tert-Bu H 346. A10 H H H H H tert-Bu H 347. A11 H H H H Htert-Bu H 348. A12 H H H H H tert-Bu H 349. A13 H H H H H tert-Bu H 350.A14 H H H H H tert-Bu H 351. A15 H H H H H tert-Bu H 352. A16 H H H H Htert-Bu H 353. A17 H H H H H tert-Bu H 354. A18 H H H H H tert-Bu H 355.A19 H H H H H tert-Bu H 356. A20 H H H H H tert-Bu H 357. A21 H H H H Htert-Bu H 358. A22 H H H H H tert-Bu H 359. A23 H H H H H tert-Bu H 360.A24 H H H H H tert-Bu H 361. A25 H H H H H tert-Bu H 362. A26 H H H H Htert-Bu H 363. A27 H H H H H tert-Bu H 364. A28 H H H H H tert-Bu H 365.A1 H H H H H H Me 366. A2 H H H H H H Me 367. A3 H H H H H H Me 368. A4H H H H H H Me 369. A5 H H H H H H Me 370. A6 H H H H H H Me 371. A7 H HH H H H Me 372. A8 H H H H H H Me 373. A9 H H H H H H Me 374. A10 H H HH H H Me 375. A11 H H H H H H Me 376. A12 H H H H H H Me 377. A13 H H HH H H Me 378. A14 H H H H H H Me 379. A15 H H H H H H Me 380. A16 H H HH H H Me 381. A17 H H H H H H Me 382. A18 H H H H H H Me 383. A19 H H HH H H Me 384. A20 H H H H H H Me 385. A21 H H H H H H Me 386. A22 H H HH H H Me 387. A23 H H H H H H Me 388. A24 H H H H H H Me 389. A25 H H HH H H Me 390. A26 H H H H H H Me 391. A27 H H H H H H Me 392. A28 H H HH H H Me 393. A1 H H H H H H tert-Bu 394. A2 H H H H H H tert-Bu 395. A3H H H H H H tert-Bu 396. A4 H H H H H H tert-Bu 397. A5 H H H H H Htert-Bu 398. A6 H H H H H H tert-Bu 399. A7 H H H H H H tert-Bu 400. A8H H H H H H tert-Bu 401. A9 H H H H H H tert-Bu 402. A10 H H H H H Htert-Bu 403. A11 H H H H H H tert-Bu 404. A12 H H H H H H tert-Bu 405.A13 H H H H H H tert-Bu 406. A14 H H H H H H tert-Bu 407. A15 H H H H HH tert-Bu 408. A16 H H H H H H tert-Bu 409. A17 H H H H H H tert-Bu 410.A18 H H H H H H tert-Bu 411. A19 H H H H H H tert-Bu 412. A20 H H H H HH tert-Bu 413. A21 H H H H H H tert-Bu 414. A22 H H H H H H tert-Bu 415.A23 H H H H H H tert-Bu 416. A24 H H H H H H tert-Bu 417. A25 H H H H HH tert-Bu 418. A26 H H H H H H tert-Bu 419. A27 H H H H H H tert-Bu 420.A28 H H H H H H tert-Bu 421. A1 —CH═CH—CH═CH— H H H H H 422. A2—CH═CH—CH═CH— H H H H H 423. A3 —CH═CH—CH═CH— H H H H H 424. A4—CH═CH—CH═CH— H H H H H 425. A5 —CH═CH—CH═CH— H H H H H 426. A6—CH═CH—CH═CH— H H H H H 427. A7 —CH═CH—CH═CH— H H H H H 428. A8—CH═CH—CH═CH— H H H H H 429. A9 —CH═CH—CH═CH— H H H H H 430. A10—CH═CH—CH═CH— H H H H H 431. A11 —CH═CH—CH═CH— H H H H H 432. A12—CH═CH—CH═CH— H H H H H 433. A13 —CH═CH—CH═CH— H H H H H 434. A14—CH═CH—CH═CH— H H H H H 435. A15 —CH═CH—CH═CH— H H H H H 436. A16—CH═CH—CH═CH— H H H H H 437. A17 —CH═CH—CH═CH— H H H H H 438. A18—CH═CH—CH═CH— H H H H H 439. A19 —CH═CH—CH═CH— H H H H H 440. A20—CH═CH—CH═CH— H H H H H 441. A21 —CH═CH—CH═CH— H H H H H 442. A22—CH═CH—CH═CH— H H H H H 443. A23 —CH═CH—CH═CH— H H H H H 444. A24—CH═CH—CH═CH— H H H H H 445. A25 —CH═CH—CH═CH— H H H H H 446. A26—CH═CH—CH═CH— H H H H H 447. A27 —CH═CH—CH═CH— H H H H H 448. A28—CH═CH—CH═CH— H H H H H 449. A1 H H H —CH═CH—CH═CH— H H 450. A2 H H H—CH═CH—CH═CH— H H 451. A3 H H H —CH═CH—CH═CH— H H 452. A4 H H H—CH═CH—CH═CH— H H 453. A5 H H H —CH═CH—CH═CH— H H 454. A6 H H H—CH═CH—CH═CH— H H 455. A7 H H H —CH═CH—CH═CH— H H 456. A8 H H H—CH═CH—CH═CH— H H 457. A9 H H H —CH═CH—CH═CH— H H 458. A10 H H H—CH═CH—CH═CH— H H 459. A11 H H H —CH═CH—CH═CH— H H 460. A12 H H H—CH═CH—CH═CH— H H 461. A13 H H H —CH═CH—CH═CH— H H 462. A14 H H H—CH═CH—CH═CH— H H 463. A15 H H H —CH═CH—CH═CH— H H 464. A16 H H H—CH═CH—CH═CH— H H 465. A17 H H H —CH═CH—CH═CH— H H 466. A18 H H H—CH═CH—CH═CH— H H 467. A19 H H H —CH═CH—CH═CH— H H 468. A20 H H H—CH═CH—CH═CH— H H 469. A21 H H H —CH═CH—CH═CH— H H 470. A22 H H H—CH═CH—CH═CH— H H 471. A23 H H H —CH═CH—CH═CH— H H 472. A24 H H H—CH═CH—CH═CH— H H 473. A25 H H H —CH═CH—CH═CH— H H 474. A26 H H H—CH═CH—CH═CH— H H 475. A27 H H H —CH═CH—CH═CH— H H 476. A28 H H H—CH═CH—CH═CH— H H 477. A1 H H H H H —CH═CH—CH═CH— 478. A2 H H H H H—CH═CH—CH═CH— 479. A3 H H H H H —CH═CH—CH═CH— 480. A4 H H H H H—CH═CH—CH═CH— 481. A5 H H H H H —CH═CH—CH═CH— 482. A6 H H H H H—CH═CH—CH═CH— 483. A7 H H H H H —CH═CH—CH═CH— 484. A8 H H H H H—CH═CH—CH═CH— 485. A9 H H H H H —CH═CH—CH═CH— 486. A10 H H H H H—CH═CH—CH═CH— 487. A11 H H H H H —CH═CH—CH═CH— 488. A12 H H H H H—CH═CH—CH═CH— 489. A13 H H H H H —CH═CH—CH═CH— 490. A14 H H H H H—CH═CH—CH═CH— 491. A15 H H H H H —CH═CH—CH═CH— 492. A16 H H H H H—CH═CH—CH═CH— 493. A17 H H H H H —CH═CH—CH═CH— 494. A18 H H H H H—CH═CH—CH═CH— 495. A19 H H H H H —CH═CH—CH═CH— 496. A20 H H H H H—CH═CH—CH═CH— 497. A21 H H H H H —CH═CH—CH═CH— 498. A22 H H H H H—CH═CH—CH═CH— 499. A23 H H H H H —CH═CH—CH═CH— 500. A24 H H H H H—CH═CH—CH═CH— 501. A25 H H H H H —CH═CH—CH═CH— 502. A26 H H H H H—CH═CH—CH═CH— 503. A27 H H H H H —CH═CH—CH═CH— 504. A28 H H H H H—CH═CH—CH═CH—wherein A is:

C. The OLEDs and the Devices of the Present Disclosure

In another aspect, the present disclosure also provides an OLED devicecomprising an organic layer that contains a compound as disclosed in theabove compounds section of the present disclosure.

In some embodiments, the organic layer may comprise a compound ofFormula I:

wherein M is Pt or Pd; rings A, B, C, and D are each independently 5- or6-membered aryl or heteroaryl rings; R^(A), R^(B), R^(C), and R^(D) eachindependently represent zero, mono, or up to maximum allowedsubstitutions to its associated ring; Z¹, Z², Z³ and Z⁴ are eachindependently C or N; L¹, L², L³, L⁴ are each independently a directbond, BR, BRR′, NR, PR, O, S, Se, C═O, S═O, SO₂, CR′R″, SiR′R″, GeR′R″,or combinations thereof; n is 0 or 1; each of R, R′, and R″ isindependently a hydrogen or a substituent selected from the groupconsisting of the general substituents defined herein; each of R^(A),R^(B), R^(C), and R^(D) is independently a hydrogen, or a substituentselected from the group consisting of the general substituents definedherein, with at least one of R^(A), R^(B), R^(C), and R^(D) comprising astructure of Formula II or Formula III:

X¹-X²⁴ are each independently C or N; each of R^(E)-R^(J) has the samedefinition as that of R^(A), R^(B), R^(C), or R^(D); the maximum numberof N atoms that can connect with each other is two;

represents a single bond or a double bond; and any two adjacent R^(A),R^(B), R^(C), R^(D), R, R′, R″ substituents can be joined to form aring, with a proviso that none of rings A, B, C, and D is anN-heterocyclic carbene ligand.

In some embodiments, the organic layer may be an emissive layer and thecompound as described herein may be an emissive dopant or a non-emissivedopant.

In some embodiments, the organic layer may further comprise a host,wherein the host comprises a triphenylene containing benzo-fusedthiophene or benzo-fused furan, wherein any substituent in the host isan unfused substituent independently selected from the group consistingof C_(n)H_(2n+1), OC_(n)H_(2n+1), OAr₁, N(C_(n)H_(2n+1))₂, N(Ar₁)(Ar₂).CH═CH—C_(n)H_(2n+1), C≡CC_(n)H_(2n+1), Ar₁, Ar₁-Ar₂. C_(n)H_(2n)—Ar₁, orno substitution, wherein n is from 1 to 10; and wherein Ar₁ and Ar₂ areindependently selected from the group consisting of benzene, biphenyl,naphthalene, triphenylene, carbazole, and heteroaromatic analogsthereof.

In some embodiments, the organic layer may further comprise a host,wherein host comprises at least one chemical moiety selected from thegroup consisting of naphthalene, fluorene, triphenylene, carbazole,indolocarbazole, dibenzothiphene, dibenzofuran, dibenzoselenophene,5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracene, aza-naphthalene,aza-fluorene, aza-triphenylene, aza-carbazole, aza-indolocarbazole,aza-dibenzothiophene, aza-dibenzofuran, aza-dibenzoselenophene, andaza-(5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracene).

In some embodiments, the host may be selected from the group consistingof:

and combinations thereof.

In some embodiments, the organic layer may further comprise a host,wherein the host comprises a metal complex.

In some embodiments, the compound as described herein may be asensitizer; wherein the device may further comprise an acceptor; andwherein the acceptor may be selected from the group consisting offluorescent emitter, delayed fluorescence emitter, and combinationthereof.

In yet another aspect, the OLED of the present disclosure may alsocomprise an emissive region containing a compound as disclosed in theabove compounds section of the present disclosure.

In some embodiments, the emissive region may comprise a compound ofFormula I:

wherein M is Pt or Pd; rings A, B, C, and D are each independently 5- or6-membered aryl or heteroaryl rings; R^(A), R^(B), R^(C), and R^(D) eachindependently represent zero, mono, or up to maximum allowedsubstitutions to its associated ring; Z¹, Z², Z³ and Z⁴ are eachindependently C or N; L¹, L², L³, L⁴ are each independently a directbond, BR, BRR′, NR, PR, O, S, Se, C═O, S═O, SO₂, CR′R″, SiR′R″, GeR′R″,or combinations thereof; n is 0 or 1; each of R, R′, and R″ isindependently a hydrogen or a substituent selected from the groupconsisting of the general substituents defined herein; each of R^(A),R^(B), R^(C), and R^(D) is independently a hydrogen, or a substituentselected from the group consisting of the general substituents definedherein, with at least one of R^(A), R^(B), R^(C), and R^(D) comprising astructure of Formula II or Formula III:

X¹-X²⁴ are each independently C or N; each of R^(E)-R^(J) has the samedefinition as that of R^(A), R^(B), R^(C), or R^(D); the maximum numberof N atoms that can connect with each other is two;

represents a single bond or a double bond; and any two adjacent R^(A),R^(B), R^(C), R^(D), R, R′, R″ substituents can be joined to form aring, with a proviso that none of rings A, B, C, and D is anN-heterocyclic carbene ligand.

In some embodiments, at least one of the anode, the cathode, or a newlayer disposed over the organic emissive layer functions as anenhancement layer. The enhancement layer comprises a plasmonic materialexhibiting surface plasmon resonance that non-radiatively couples to theemitter material and transfers excited state energy from the emittermaterial to non-radiative mode of surface plasmon polariton. Theenhancement layer is provided no more than a threshold distance awayfrom the organic emissive layer, wherein the emitter material has atotal non-radiative decay rate constant and a total radiative decay rateconstant due to the presence of the enhancement layer and the thresholddistance is where the total non-radiative decay rate constant is equalto the total radiative decay rate constant. In some embodiments, theOLED further comprises an outcoupling layer. In some embodiments, theoutcoupling layer is disposed over the enhancement layer on the oppositeside of the organic emissive layer. In some embodiments, the outcouplinglayer is disposed on opposite side of the emissive layer from theenhancement layer but still outcouples energy from the surface plasmonmode of the enhancement layer. The outcoupling layer scatters the energyfrom the surface plasmon polaritons. In some embodiments this energy isscattered as photons to free space. In other embodiments, the energy isscattered from the surface plasmon mode into other modes of the devicesuch as but not limited to the organic waveguide mode, the substratemode, or another waveguiding mode. If energy is scattered to thenon-free space mode of the OLED other outcoupling schemes could beincorporated to extract that energy to free space. In some embodiments,one or more intervening layer can be disposed between the enhancementlayer and the outcoupling layer. The examples for interventing layer(s)can be dielectric materials, including organic, inorganic, perovskites,oxides, and may include stacks and/or mixtures of these materials.

The enhancement layer modifies the effective properties of the medium inwhich the emitter material resides resulting in any or all of thefollowing: a decreased rate of emission, a modification of emissionline-shape, a change in emission intensity with angle, a change in thestability of the emitter material, a change in the efficiency of theOLED, and reduced efficiency roll-off of the OLED device. Placement ofthe enhancement layer on the cathode side, anode side, or on both sidesresults in OLED devices which take advantage of any of theabove-mentioned effects. In addition to the specific functional layersmentioned herein and illustrated in the various OLED examples shown inthe figures, the OLEDs according to the present disclosure may includeany of the other functional layers often found in OLEDs.

The enhancement layer can be comprised of plasmonic materials, opticallyactive metamaterials, or hyperbolic metamaterials. As used herein, aplasmonic material is a material in which the real part of thedielectric constant crosses zero in the visible or ultraviolet region ofthe electromagnetic spectrum. In some embodiments, the plasmonicmaterial includes at least one metal. In such embodiments the metal mayinclude at least one of Ag, Al, Au, Ir, Pt, Ni, Cu, W, Ta, Fe, Cr, Mg,Ga, Rh, Ti, Ru, Pd, In, Bi, Ca alloys or mixtures of these materials,and stacks of these materials. In general, a metamaterial is a mediumcomposed of different materials where the medium as a whole actsdifferently than the sum of its material parts. In particular, we defineoptically active metamaterials as materials which have both negativepermittivity and negative permeability. Hyperbolic metamaterials, on theother hand, are anisotropic media in which the permittivity orpermeability are of different sign for different spatial directions.Optically active metamaterials and hyperbolic metamaterials are strictlydistinguished from many other photonic structures such as DistributedBragg Reflectors (“DBRs”) in that the medium should appear uniform inthe direction of propagation on the length scale of the wavelength oflight. Using terminology that one skilled in the art can understand: thedielectric constant of the metamaterials in the direction of propagationcan be described with the effective medium approximation. Plasmonicmaterials and metamaterials provide methods for controlling thepropagation of light that can enhance OLED performance in a number ofways.

In some embodiments, the enhancement layer is provided as a planarlayer. In other embodiments, the enhancement layer has wavelength-sizedfeatures that are arranged periodically, quasi-periodically, orrandomly, or sub-wavelength-sized features that are arrangedperiodically, quasi-periodically, or randomly. In some embodiments, thewavelength-sized features and the sub-wavelength-sized features havesharp edges.

In some embodiments, the outcoupling layer has wavelength-sized featuresthat are arranged periodically, quasi-periodically, or randomly, orsub-wavelength-sized features that are arranged periodically,quasi-periodically, or randomly. In some embodiments, the outcouplinglayer may be composed of a plurality of nanoparticles and in otherembodiments the outcoupling layer is composed of a plurality ofnanoparticles disposed over a material. In these embodiments theoutcoupling may be tunable by at least one of varying a size of theplurality of nanoparticles, varying a shape of the plurality ofnanoparticles, changing a material of the plurality of nanoparticles,adjusting a thickness of the material, changing the refractive index ofthe material or an additional layer disposed on the plurality ofnanoparticles, varying a thickness of the enhancement layer, and/orvarying the material of the enhancement layer. The plurality ofnanoparticles of the device may be formed from at least one of metal,dielectric material, semiconductor materials, an alloy of metal, amixture of dielectric materials, a stack or layering of one or morematerials, and/or a core of one type of material and that is coated witha shell of a different type of material. In some embodiments, theoutcoupling layer is composed of at least metal nanoparticles whereinthe metal is selected from the group consisting of Ag, Al, Au, Ir, Pt,Ni, Cu, W, Ta, Fe, Cr, Mg, Ga, Rh, Ti, Ru, Pd, In, Bi, Ca, alloys ormixtures of these materials, and stacks of these materials. Theplurality of nanoparticles may have additional layer disposed over them.In some embodiments, the polarization of the emission can be tuned usingthe outcoupling layer. Varying the dimensionality and periodicity of theoutcoupling layer can select a type of polarization that ispreferentially outcoupled to air. In some embodiments the outcouplinglayer also acts as an electrode of the device.

In yet another aspect, the present disclosure also provides a consumerproduct comprising an organic light-emitting device (OLED) having ananode; a cathode; and an organic layer disposed between the anode andthe cathode, wherein the organic layer may comprise a compound asdisclosed in the above compounds section of the present disclosure.

In yet another aspect, the present disclosure also provides a consumerproduct comprising an organic light-emitting device (OLED) having ananode; a cathode; and an organic layer disposed between the anode andthe cathode, wherein the organic layer may comprise a compound asdisclosed in the above compounds section of the present disclosure.

In some embodiments, the consumer product comprises an organiclight-emitting device (OLED) having an anode; a cathode; and an organiclayer disposed between the anode and the cathode, wherein the organiclayer may comprise a compound of Formula I:

wherein M is Pt or Pd; rings A, B, C, and D are each independently 5- or6-membered aryl or heteroaryl rings; R^(A), R^(B), R^(C), and R^(D) eachindependently represent zero, mono, or up to maximum allowedsubstitutions to its associated ring; Z¹, Z², Z³ and Z⁴ are eachindependently C or N; L¹, L², L³, L⁴ are each independently a directbond, BR, BRR′, NR, PR, O, S, Se, C═O, S═O, SO₂, CR′R″, SiR′R″, GeR′R″,or combinations thereof; n is 0 or 1; each of R, R′, and R″ isindependently a hydrogen or a substituent selected from the groupconsisting of the general substituents defined herein; each of R^(A),R^(B), R^(C), and R^(D) is independently a hydrogen, or a substituentselected from the group consisting of the general substituents definedherein, with at least one of R^(A), R^(B), R^(C), and R^(D) comprising astructure of Formula II or Formula III:

X¹-X²⁴ are each independently C or N; each of R^(E)-R^(J) has the samedefinition as that of R^(A), R^(B), R^(C), or R^(D); the maximum numberof N atoms that can connect with each other is two;

represents a single bond or a double bond; and any two adjacent R^(A),R^(B), R^(C), R^(D), R, R′, R″ substituents can be joined to form aring, with a proviso that none of rings A, B, C, and D is anN-heterocyclic carbene ligand.

In some embodiments, the consumer product can be one of a flat paneldisplay, a computer monitor, a medical monitor, a television, abillboard, a light for interior or exterior illumination and/orsignaling, a heads-up display, a fully or partially transparent display,a flexible display, a laser printer, a telephone, a cell phone, tablet,a phablet, a personal digital assistant (PDA), a wearable device, alaptop computer, a digital camera, a camcorder, a viewfinder, amicro-display that is less than 2 inches diagonal, a 3-D display, avirtual reality or augmented reality display, a vehicle, a video wallcomprising multiple displays tiled together, a theater or stadiumscreen, a light therapy device, and a sign.

Generally, an OLED comprises at least one organic layer disposed betweenand electrically connected to an anode and a cathode. When a current isapplied, the anode injects holes and the cathode injects electrons intothe organic layer(s). The injected holes and electrons each migratetoward the oppositely charged electrode. When an electron and holelocalize on the same molecule, an “exciton,” which is a localizedelectron-hole pair having an excited energy state, is formed. Light isemitted when the exciton relaxes via a photoemissive mechanism. In somecases, the exciton may be localized on an excimer or an exciplex.Non-radiative mechanisms, such as thermal relaxation, may also occur,but are generally considered undesirable.

Several OLED materials and configurations are described in U.S. Pat.Nos. 5,844,363, 6,303,238, and 5,707,745, which are incorporated hereinby reference in their entirety.

The initial OLEDs used emissive molecules that emitted light from theirsinglet states (“fluorescence”) as disclosed, for example, in U.S. Pat.No. 4,769,292, which is incorporated by reference in its entirety.Fluorescent emission generally occurs in a time frame of less than 10nanoseconds.

More recently, OLEDs having emissive materials that emit light fromtriplet states (“phosphorescence”) have been demonstrated. Baldo et al.,“Highly Efficient Phosphorescent Emission from OrganicElectroluminescent Devices,” Nature, vol. 395, 151-154, 1998;(“Baldo-I”) and Baldo et al., “Very high-efficiency green organiclight-emitting devices based on electrophosphorescence,” Appl. Phys.Lett., vol. 75, No. 3, 4-6 (1999) (“Baldo-II”), are incorporated byreference in their entireties. Phosphorescence is described in moredetail in U.S. Pat. No. 7,279,704 at cols. 5-6, which are incorporatedby reference.

FIG. 1 shows an organic light emitting device 100. The figures are notnecessarily drawn to scale. Device 100 may include a substrate 110, ananode 115, a hole injection layer 120, a hole transport layer 125, anelectron blocking layer 130, an emissive layer 135, a hole blockinglayer 140, an electron transport layer 145, an electron injection layer150, a protective layer 155, a cathode 160, and a barrier layer 170.Cathode 160 is a compound cathode having a first conductive layer 162and a second conductive layer 164. Device 100 may be fabricated bydepositing the layers described, in order. The properties and functionsof these various layers, as well as example materials, are described inmore detail in U.S. Pat. No. 7,279,704 at cols. 6-10, which areincorporated by reference.

More examples for each of these layers are available. For example, aflexible and transparent substrate-anode combination is disclosed inU.S. Pat. No. 5,844,363, which is incorporated by reference in itsentirety. An example of a p-doped hole transport layer is m-MTDATA dopedwith F₄-TCNQ at a molar ratio of 50:1, as disclosed in U.S. PatentApplication Publication No. 2003/0230980, which is incorporated byreference in its entirety. Examples of emissive and host materials aredisclosed in U.S. Pat. No. 6,303,238 to Thompson et al., which isincorporated by reference in its entirety. An example of an n-dopedelectron transport layer is BPhen doped with Li at a molar ratio of 1:1,as disclosed in U.S. Patent Application Publication No. 2003/0230980,which is incorporated by reference in its entirety. U.S. Pat. Nos.5,703,436 and 5,707,745, which are incorporated by reference in theirentireties, disclose examples of cathodes including compound cathodeshaving a thin layer of metal such as Mg: Ag with an overlyingtransparent, electrically-conductive, sputter-deposited ITO layer. Thetheory and use of blocking layers is described in more detail in U.S.Pat. No. 6,097,147 and U.S. Patent Application Publication No.2003/0230980, which are incorporated by reference in their entireties.Examples of injection layers are provided in U.S. Patent ApplicationPublication No. 2004/0174116, which is incorporated by reference in itsentirety. A description of protective layers may be found in U. S.Patent Application Publication No. 2004/0174116, which is incorporatedby reference in its entirety.

FIG. 2 shows an inverted OLED 200. The device includes a substrate 210,a cathode 215, an emissive layer 220, a hole transport layer 225, and ananode 230. Device 200 may be fabricated by depositing the layersdescribed, in order. Because the most common OLED configuration has acathode disposed over the anode, and device 200 has cathode 215 disposedunder anode 230, device 200 may be referred to as an “inverted” OLED.Materials similar to those described with respect to device 100 may beused in the corresponding layers of device 200. FIG. 2 provides oneexample of how some layers may be omitted from the structure of device100.

The simple layered structure illustrated in FIGS. 1 and 2 is provided byway of non-limiting example, and it is understood that embodiments ofthe present disclosure may be used in connection with a wide variety ofother structures. The specific materials and structures described areexemplary in nature, and other materials and structures may be used.Functional OLEDs may be achieved by combining the various layersdescribed in different ways, or layers may be omitted entirely, based ondesign, performance, and cost factors. Other layers not specificallydescribed may also be included. Materials other than those specificallydescribed may be used. Although many of the examples provided hereindescribe various layers as comprising a single material, it isunderstood that combinations of materials, such as a mixture of host anddopant, or more generally a mixture, may be used. Also, the layers mayhave various sublayers. The names given to the various layers herein arenot intended to be strictly limiting. For example, in device 200, holetransport layer 225 transports holes and injects holes into emissivelayer 220, and may be described as a hole transport layer or a holeinjection layer. In one embodiment, an OLED may be described as havingan “organic layer” disposed between a cathode and an anode. This organiclayer may comprise a single layer, or may further comprise multiplelayers of different organic materials as described, for example, withrespect to FIGS. 1 and 2.

Structures and materials not specifically described may also be used,such as OLEDs comprised of polymeric materials (PLEDs) such as disclosedin U.S. Pat. No. 5,247,190 to Friend et al., which is incorporated byreference in its entirety. By way of further example, OLEDs having asingle organic layer may be used. OLEDs may be stacked, for example asdescribed in U.S. Pat. No. 5,707,745 to Forrest et al, which isincorporated by reference in its entirety. The OLED structure maydeviate from the simple layered structure illustrated in FIGS. 1 and 2.For example, the substrate may include an angled reflective surface toimprove out-coupling, such as a mesa structure as described in U.S. Pat.No. 6,091,195 to Forrest et al., and/or a pit structure as described inU.S. Pat. No. 5,834,893 to Bulovic et al., which are incorporated byreference in their entireties.

Unless otherwise specified, any of the layers of the various embodimentsmay be deposited by any suitable method. For the organic layers,preferred methods include thermal evaporation, ink-jet, such asdescribed in U.S. Pat. Nos. 6,013,982 and 6,087,196, which areincorporated by reference in their entireties, organic vapor phasedeposition (OVPD), such as described in U.S. Pat. No. 6,337,102 toForrest et al., which is incorporated by reference in its entirety, anddeposition by organic vapor jet printing (OVJP), such as described inU.S. Pat. No. 7,431,968, which is incorporated by reference in itsentirety. Other suitable deposition methods include spin coating andother solution based processes. Solution based processes are preferablycarried out in nitrogen or an inert atmosphere. For the other layers,preferred methods include thermal evaporation. Preferred patterningmethods include deposition through a mask, cold welding such asdescribed in U.S. Pat. Nos. 6,294,398 and 6,468,819, which areincorporated by reference in their entireties, and patterning associatedwith some of the deposition methods such as ink-jet and organic vaporjet printing (OVJP). Other methods may also be used. The materials to bedeposited may be modified to make them compatible with a particulardeposition method. For example, substituents such as alkyl and arylgroups, branched or unbranched, and preferably containing at least 3carbons, may be used in small molecules to enhance their ability toundergo solution processing. Substituents having 20 carbons or more maybe used, and 3-20 carbons are a preferred range. Materials withasymmetric structures may have better solution processability than thosehaving symmetric structures, because asymmetric materials may have alower tendency to recrystallize. Dendrimer substituents may be used toenhance the ability of small molecules to undergo solution processing.

Devices fabricated in accordance with embodiments of the presentdisclosure may further optionally comprise a barrier layer. One purposeof the barrier layer is to protect the electrodes and organic layersfrom damaging exposure to harmful species in the environment includingmoisture, vapor and/or gases, etc. The barrier layer may be depositedover, under or next to a substrate, an electrode, or over any otherparts of a device including an edge. The barrier layer may comprise asingle layer, or multiple layers. The barrier layer may be formed byvarious known chemical vapor deposition techniques and may includecompositions having a single phase as well as compositions havingmultiple phases. Any suitable material or combination of materials maybe used for the barrier layer. The barrier layer may incorporate aninorganic or an organic compound or both. The preferred barrier layercomprises a mixture of a polymeric material and a non-polymeric materialas described in U.S. Pat. No. 7,968,146, PCT Pat. Application Nos.PCT/US2007/023098 and PCT/US2009/042829, which are herein incorporatedby reference in their entireties. To be considered a “mixture”, theaforesaid polymeric and non-polymeric materials comprising the barrierlayer should be deposited under the same reaction conditions and/or atthe same time. The weight ratio of polymeric to non-polymeric materialmay be in the range of 95:5 to 5:95. The polymeric material and thenon-polymeric material may be created from the same precursor material.In one example, the mixture of a polymeric material and a non-polymericmaterial consists essentially of polymeric silicon and inorganicsilicon.

Devices fabricated in accordance with embodiments of the presentdisclosure can be incorporated into a wide variety of electroniccomponent modules (or units) that can be incorporated into a variety ofelectronic products or intermediate components. Examples of suchelectronic products or intermediate components include display screens,lighting devices such as discrete light source devices or lightingpanels, etc. that can be utilized by the end-user product manufacturers.Such electronic component modules can optionally include the drivingelectronics and/or power source(s). Devices fabricated in accordancewith embodiments of the present disclosure can be incorporated into awide variety of consumer products that have one or more of theelectronic component modules (or units) incorporated therein. A consumerproduct comprising an OLED that includes the compound of the presentdisclosure in the organic layer in the OLED is disclosed. Such consumerproducts would include any kind of products that include one or morelight source(s) and/or one or more of some type of visual displays. Someexamples of such consumer products include flat panel displays, curveddisplays, computer monitors, medical monitors, televisions, billboards,lights for interior or exterior illumination and/or signaling, heads-updisplays, fully or partially transparent displays, flexible displays,Tollable displays, foldable displays, stretchable displays, laserprinters, telephones, mobile phones, tablets, phablets, personal digitalassistants (PDAs), wearable devices, laptop computers, digital cameras,camcorders, viewfinders, micro-displays (displays that are less than 2inches diagonal), 3-D displays, virtual reality or augmented realitydisplays, vehicles, video walls comprising multiple displays tiledtogether, theater or stadium screen, a light therapy device, and a sign.Various control mechanisms may be used to control devices fabricated inaccordance with the present disclosure, including passive matrix andactive matrix. Many of the devices are intended for use in a temperaturerange comfortable to humans, such as 18 degrees C. to 30 degrees C., andmore preferably at room temperature (20-25° C.), but could be usedoutside this temperature range, for example, from −40 degree C. to +80°C.

More details on OLEDs, and the definitions described above, can be foundin U.S. Pat. No. 7,279,704, which is incorporated herein by reference inits entirety.

The materials and structures described herein may have applications indevices other than OLEDs. For example, other optoelectronic devices suchas organic solar cells and organic photodetectors may employ thematerials and structures. More generally, organic devices, such asorganic transistors, may employ the materials and structures.

In some embodiments, the OLED has one or more characteristics selectedfrom the group consisting of being flexible, being reliable, beingfoldable, being stretchable, and being curved. In some embodiments, theOLED is transparent or semi-transparent. In some embodiments, the OLEDfurther comprises a layer comprising carbon nanotubes.

In some embodiments, the OLED further comprises a layer comprising adelayed fluorescent emitter. In some embodiments, the OLED comprises aRGB pixel arrangement or white plus color filter pixel arrangement. Insome embodiments, the OLED is a mobile device, a hand held device, or awearable device. In some embodiments, the OLED is a display panel havingless than 10 inch diagonal or 50 square inch area. In some embodiments,the OLED is a display panel having at least 10 inch diagonal or 50square inch area. In some embodiments, the OLED is a lighting panel.

In some embodiments, the compound can be an emissive dopant. In someembodiments, the compound can produce emissions via phosphorescence,fluorescence, thermally activated delayed fluorescence, i.e., TADF (alsoreferred to as E-type delayed fluorescence; see, e.g., U.S. applicationSer. No. 15/700,352, which is hereby incorporated by reference in itsentirety), triplet-triplet annihilation, or combinations of theseprocesses. In some embodiments, the emissive dopant can be a racemicmixture, or can be enriched in one enantiomer. In some embodiments, thecompound can be homoleptic (each ligand is the same). In someembodiments, the compound can be heteroleptic (at least one ligand isdifferent from others). When there are more than one ligand coordinatedto a metal, the ligands can all be the same in some embodiments. In someother embodiments, at least one ligand is different from the otherligands. In some embodiments, every ligand can be different from eachother. This is also tree in embodiments where a ligand being coordinatedto a metal can be linked with other ligands being coordinated to thatmetal to form a tridentate, tetradentate, pentadentate, or hexadentateligands. Thus, where the coordinating ligands are being linked together,all of the ligands can be the same in some embodiments, and at least oneof the ligands being linked can be different from the other ligand(s) insome other embodiments.

In some embodiments, the compound can be used as a phosphorescentsensitizer in an OLED where one or multiple layers in the OLED containsan acceptor in the form of one or more fluorescent and/or delayedfluorescence emitters. In some embodiments, the compound can be used asone component of an exciplex to be used as a sensitizer. As aphosphorescent sensitizer, the compound must be capable of energytransfer to the acceptor and the acceptor will emit the energy orfurther transfer energy to a final emitter. The acceptor concentrationscan range from 0.001% to 100%. The acceptor could be in either the samelayer as the phosphorescent sensitizer or in one or more differentlayers. In some embodiments, the acceptor is a TADF emitter. In someembodiments, the acceptor is a fluorescent emitter. In some embodiments,the emission can arise from any or all of the sensitizer, acceptor, andfinal emitter

According to another aspect, a formulation comprising the compounddescribed herein is also disclosed.

The OLED disclosed herein can be incorporated into one or more of aconsumer product, an electronic component module, and a lighting panel.The organic layer can be an emissive layer and the compound can be anemissive dopant in some embodiments, while the compound can be anon-emissive dopant in other embodiments.

In yet another aspect of the present disclosure, a formulation thatcomprises the novel compound disclosed herein is described. Theformulation can include one or more components selected from the groupconsisting of a solvent, a host, a hole injection material, holetransport material, electron blocking material, hole blocking material,and an electron transport material, disclosed herein.

The present disclosure encompasses any chemical structure comprising thenovel compound of the present disclosure, or a monovalent or polyvalentvariant thereof. In other words, the inventive compound, or a monovalentor polyvalent variant thereof, can be a part of a larger chemicalstructure. Such chemical structure can be selected from the groupconsisting of a monomer, a polymer, a macromolecule, and a supramolecule(also known as supermolecule). As used herein, a “monovalent variant ofa compound” refers to a moiety that is identical to the compound exceptthat one hydrogen has been removed and replaced with a bond to the restof the chemical structure. As used herein, a “polyvalent variant of acompound” refers to a moiety that is identical to the compound exceptthat more than one hydrogen has been removed and replaced with a bond orbonds to the rest of the chemical structure. In the instance of asupramolecule, the inventive compound can also be incorporated into thesupramolecule complex without covalent bonds.

D. Combination of the Compounds of the Present Disclosure with OtherMaterials

The materials described herein as useful for a particular layer in anorganic light emitting device may be used in combination with a widevariety of other materials present in the device. For example, emissivedopants disclosed herein may be used in conjunction with a wide varietyof hosts, transport layers, blocking layers, injection layers,electrodes and other layers that may be present. The materials describedor referred to below are non-limiting examples of materials that may beuseful in combination with the compounds disclosed herein, and one ofskill in the art can readily consult the literature to identity othermaterials that may be useful in combination.

a) Conductivity Dopants:

A charge transport layer can be doped with conductivity dopants tosubstantially alter its density of charge carriers, which will in turnalter its conductivity. The conductivity is increased by generatingcharge carriers in the matrix material, and depending on the type ofdopant, a change in the Fermi level of the semiconductor may also beachieved. Hole-transporting layer can be doped by p-type conductivitydopants and n-type conductivity dopants are used in theelectron-transporting layer.

Non-limiting examples of the conductivity dopants that may be used in anOLED in combination with materials disclosed herein are exemplifiedbelow together with references that disclose those materials:EP01617493, EP01968131, EP2020694, EP2684932, US20050139810,US20070160905, US20090167167, US2010288362, WO06081780, WO2009003455,WO2009008277, WO2009011327, WO2014009310, US2007252140, US2015060804,US20150123047, and US2012146012.

b) HIL/HTL:

A hole injecting/transporting material to be used in the presentdisclosure is not particularly limited, and any compound may be used aslong as the compound is typically used as a hole injecting/transportingmaterial. Examples of the material include, but are not limited to: aphthalocyanine or porphyrin derivative; an aromatic amine derivative; anindolocarbazole derivative; a polymer containing fluorohydrocarbon; apolymer with conductivity dopants; a conducting polymer, such asPEDOT/PSS; a self-assembly monomer derived from compounds such asphosphonic acid and silane derivatives; a metal oxide derivative, suchas MoO_(x); a p-type semiconducting organic compound, such as1,4,5,8,9,12-Hexaazatriphenylenehexacarbonitrile; a metal complex, and across-linkable compounds.

Examples of aromatic amine derivatives used in HIL or HTL include, butnot limit to the following general structures:

Each of Ar¹ to Ar⁹ is selected from the group consisting of aromatichydrocarbon cyclic compounds such as benzene, biphenyl, triphenyl,triphenylene, naphthalene, anthracene, phenalene, phenanthrene,fluorene, pyrene, chrysene, perylene, and azulene; the group consistingof aromatic heterocyclic compounds such as dibenzothiophene,dibenzofuran, dibenzoselenophene, furan, thiophene, benzofuran,benzothiophene, benzoselenophene, carbazole, indolocarbazole,pyridylindole, pyrrolodipyridine, pyrazole, imidazole, triazole,oxazole, thiazole, oxadiazole, oxatriazole, dioxazole, thiadiazole,pyridine, pyridazine, pyrimidine, pyrazine, triazine, oxazine,oxathiazine, oxadiazine, indole, benzimidazole, indazole, indoxazine,benzoxazole, benzisoxazole, benzothiazole, quinoline, isoquinoline,cinnoline, quinazoline, quinoxaline, naphthyridine, phthalazine,pteridine, xanthene, acridine, phenazine, phenothiazine, phenoxazine,benzofuropyridine, furodipyridine, benzothienopyridine,thienodipyridine, benzoselenophenopyridine, and selenophenodipyridine;and the group consisting of 2 to 10 cyclic structural units which aregroups of the same type or different types selected from the aromatichydrocarbon cyclic group and the aromatic heterocyclic group and arebonded to each other directly or via at least one of oxygen atom,nitrogen atom, sulfur atom, silicon atom, phosphorus atom, boron atom,chain structural unit and the aliphatic cyclic group. Each Ar may beunsubstituted or may be substituted by a substituent selected from thegroup consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl,heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl,cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylicacids, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl,phosphino, and combinations thereof.

In one aspect, Ar¹ to Ar⁹ is independently selected from the groupconsisting of:

wherein k is an integer from 1 to 20; X¹⁰¹ to X¹⁰⁸ is C (including CH)or N; Z¹⁰¹ is NAr¹, O, or S; Ar¹ has the same group defined above.

Examples of metal complexes used in HIL or HTL include, but are notlimited to the following general formula:

wherein Met is a metal, which can have an atomic weight greater than 40;(Y¹⁰¹-Y¹⁰²) is a bidentate ligand, Y¹⁰¹ and Y¹⁰² are independentlyselected from C, N, O, P, and S; L¹⁰¹ is an ancillary ligand; k′ is aninteger value from 1 to the maximum number of ligands that may beattached to the metal; and k′+k″ is the maximum number of ligands thatmay be attached to the metal.

In one aspect, (Y¹⁰¹-Y¹⁰²) is a 2-phenylpyridine derivative. In anotheraspect, (Y¹⁰¹-Y¹⁰²) is a carbene ligand. In another aspect, Met isselected from Ir, Pt, Os, and Zn. In a further aspect, the metal complexhas a smallest oxidation potential in solution vs. Fc⁺/Fc couple lessthan about 0.6 V.

Non-limiting examples of the HIL and HTL materials that may be used inan OLED in combination with materials disclosed herein are exemplifiedbelow together with references that disclose those materials:CN102702075, DE102012005215, EP01624500, EP01698613, EP01806334,EP01930964, EP01972613, EP01997799, EP02011790, EP02055700, EP02055701,EP1725079, EP2085382, EP2660300, EP650955, JP07-073529, JP2005112765,JP2007091719, JP2008021687, JP2014-009196, KR20110088898, KR20130077473,TW201139402, U.S. Ser. No. 06/517,957, US20020158242, US20030162053,US20050123751, US20060182993, US20060240279, US20070145888,US20070181874, US20070278938, US20080014464, US20080091025,US20080106190, US20080124572, US20080145707, US20080220265,US20080233434, US20080303417, US2008107919, US20090115320,US20090167161, US2009066235, US2011007385, US20110163302, US2011240968,US2011278551, US2012205642, US2013241401, US20140117329, US2014183517,U.S. Pat. Nos. 5,061,569, 5,639,914, WO05075451, WO07125714, WO08023550,WO08023759, WO2009145016, WO2010061824, WO2011075644, WO2012177006,WO2013018530, WO2013039073, WO2013087142, WO2013118812, WO2013120577,WO2013157367, WO2013175747, WO2014002873, WO2014015935, WO2014015937,WO2014030872, WO2014030921, WO2014034791, WO2014104514, WO2014157018.

c) EBL:

An electron blocking layer (EBL) may be used to reduce the number ofelectrons and/or excitons that leave the emissive layer. The presence ofsuch a blocking layer in a device may result in substantially higherefficiencies, and/or longer lifetime, as compared to a similar devicelacking a blocking layer. Also, a blocking layer may be used to confineemission to a desired region of an OLED. In some embodiments, the EBLmaterial has a higher LUMO (closer to the vacuum level) and/or highertriplet energy than the emitter closest to the EBL interface. In someembodiments, the EBL material has a higher LUMO (closer to the vacuumlevel) and/or higher triplet energy than one or more of the hostsclosest to the EBL interface. In one aspect, the compound used in EBLcontains the same molecule or the same functional groups used as one ofthe hosts described below.

d) Hosts:

The light emitting layer of the organic EL device of the presentdisclosure preferably contains at least a metal complex as lightemitting material, and may contain a host material using the metalcomplex as a dopant material. Examples of the host material are notparticularly limited, and any metal complexes or organic compounds maybe used as long as the triplet energy of the host is larger than that ofthe dopant. Any host material may be used with any dopant so long as thetriplet criteria is satisfied.

Examples of metal complexes used as host are preferred to have thefollowing general formula:

wherein Met is a metal; (Y¹⁰³-Y¹⁰⁴) is a bidentate ligand, Y¹⁰³ and Y¹⁰⁴are independently selected from C, N, O, P, and S; L¹⁰¹ is an anotherligand; k′ is an integer value from 1 to the maximum number of ligandsthat may be attached to the metal; and k′+k″ is the maximum number ofligands that may be attached to the metal.

In one aspect, the metal complexes are:

wherein (O—N) is a bidentate ligand, having metal coordinated to atoms Oand N.

In another aspect, Met is selected from Ir and Pt. In a further aspect,(Y¹⁰³-Y¹⁰⁴) is a carbene ligand.

In one aspect, the host compound contains at least one of the followinggroups selected from the group consisting of aromatic hydrocarbon cycliccompounds such as benzene, biphenyl, triphenyl, triphenylene,tetraphenylene, naphthalene, anthracene, phenalene, phenanthrene,fluorene, pyrene, chrysene, perylene, and azulene; the group consistingof aromatic heterocyclic compounds such as dibenzothiophene,dibenzofuran, dibenzoselenophene, furan, thiophene, benzofuran,benzothiophene, benzoselenophene, carbazole, indolocarbazole,pyridylindole, pyrrolodipyridine, pyrazole, imidazole, triazole,oxazole, thiazole, oxadiazole, oxatriazole, dioxazole, thiadiazole,pyridine, pyridazine, pyrimidine, pyrazine, triazine, oxazine,oxathiazine, oxadiazine, indole, benzimidazole, indazole, indoxazine,benzoxazole, benzisoxazole, benzothiazole, quinoline, isoquinoline,cinnoline, quinazoline, quinoxaline, naphthyridine, phthalazine,pteridine, xanthene, acridine, phenazine, phenothiazine, phenoxazine,benzofuropyridine, furodipyridine, benzothienopyridine,thienodipyridine, benzoselenophenopyridine, and selenophenodipyridine;and the group consisting of 2 to 10 cyclic structural units which aregroups of the same type or different types selected from the aromatichydrocarbon cyclic group and the aromatic heterocyclic group and arebonded to each other directly or via at least one of oxygen atom,nitrogen atom, sulfur atom, silicon atom, phosphorus atom, boron atom,chain structural unit and the aliphatic cyclic group. Each option withineach group may be unsubstituted or may be substituted by a substituentselected from the group consisting of deuterium, halogen, alkyl,cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy,amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl,heteroaryl, acyl, carboxylic acids, ether, ester, nitrile, isonitrile,sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof.

In one aspect, the host compound contains at least one of the followinggroups in the molecule:

wherein R¹⁰¹ is selected from the group consisting of hydrogen,deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl,arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl,heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acids, ether,ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, andcombinations thereof, and when it is aryl or heteroaryl, it has thesimilar definition as Ar's mentioned above, k is an integer from 0 to 20or 1 to 20. X¹⁰¹ to X¹⁰⁸ are independently selected from C (includingCH) or N. Z¹⁰¹ and Z¹⁰² are independently selected from NR¹⁰¹, O, or S.

Non-limiting examples of the host materials that may be used in an OLEDin combination with materials disclosed herein are exemplified belowtogether with references that disclose those materials: EP2034538,EP2034538A, EP2757608, JP2007254297, KR20100079458, KR20120088644,KR20120129733, KR20130115564, TW201329200, US20030175553, US20050238919,US20060280965, US20090017330, US20090030202, US20090167162,US20090302743, US20090309488, US20100012931, US20100084966,US20100187984, US2010187984, US2012075273, US2012126221, US2013009543,US2013105787, US2013175519, US2014001446, US20140183503, US20140225088,US2014034914, U.S. Pat. No. 7,154,114, WO2001039234, WO2004093207,WO2005014551, WO2005089025, WO2006072002, WO2006114966, WO2007063754,WO2008056746, WO2009003898, WO2009021126, WO2009063833, WO2009066778,WO2009066779, WO2009086028, WO2010056066, WO2010107244, WO2011081423,WO2011081431, WO2011086863, WO2012128298, WO2012133644, WO2012133649,WO2013024872, WO2013035275, WO2013081315, WO2013191404, WO2014142472,US20170263869, US20160163995, U.S. Pat. No. 9,466,803,

e) Additional Emitters:

One or more additional emitter dopants may be used in conjunction withthe compound of the present disclosure. Examples of the additionalemitter dopants are not particularly limited, and any compounds may beused as long as the compounds are typically used as emitter materials.Examples of suitable emitter materials include, but are not limited to,compounds which can produce emissions via phosphorescence, fluorescence,thermally activated delayed fluorescence, i.e., TADF (also referred toas E-type delayed fluorescence), triplet-triplet annihilation, orcombinations of these processes.

Non-limiting examples of the emitter materials that may be used in anOLED in combination with materials disclosed herein are exemplifiedbelow together with references that disclose those materials:CN103694277, CN1696137, EB01238981, EP01239526, EP01961743, EP1239526,EP1244155, EP1642951, EP1647554, EP1841834, EP1841834B, EP2062907,EP2730583, JP2012074444, JP2013110263, JP4478555, KR1020090133652,KR20120032054, KR20130043460, TW201332980, U.S. Ser. No. 06/699,599,U.S. Ser. No. 06/916,554, US20010019782, US20020034656, US20030068526,US20030072964, US20030138657, US20050123788, US20050244673,US2005123791, US2005260449, US20060008670, US20060065890, US20060127696,US20060134459, US20060134462, US20060202194, US20060251923,US20070034863, US20070087321, US20070103060, US20070111026,US20070190359, US20070231600, US2007034863, US2007104979, US2007104980,US2007138437, US2007224450, US2007278936, US20080020237, US20080233410,US20080261076, US20080297033, US200805851, US2008161567, US2008210930,US20090039776, US20090108737, US20090115322, US20090179555,US2009085476, US2009104472, US20100090591, US20100148663, US20100244004,US20100295032, US2010102716, US2010105902, US2010244004, US2010270916,US20110057559, US20110108822, US20110204333, US2011215710, US2011227049,US2011285275, US2012292601, US20130146848, US2013033172, US2013165653,US2013181190, US2013334521, US20140246656, US2014103305, U.S. Pat. Nos.6,303,238, 6,413,656, 6,653,654, 6,670,645, 6,687,266, 6,835,469,6,921,915, 7,279,704, 7,332,232, 7,378,162, 7,534,505, 7,675,228,7,728,137, 7,740,957, 7,759,489, 7,951,947, 8,067,099, 8,592,586,8,871,361, WO06081973, WO06121811, WO07018067, WO07108362, WO07115970,WO07115981, WO08035571, WO2002015645, WO2003040257, WO2005019373,WO2006056418, WO2008054584, WO2008078800, WO2008096609, WO2008101842,WO2009000673, WO2009050281, WO2009100991, WO2010028151, WO2010054731,WO2010086089, WO2010118029, WO2011044988, WO2011051404, WO2011107491,WO2012020327, WO2012163471, WO2013094620, WO2013107487, WO2013174471,WO2014007565, WO2014008982, WO2014023377, WO2014024131, WO2014031977,WO2014038456, WO2014112450.

f) HBL:

A hole blocking layer (HBL) may be used to reduce the number of holesand/or excitons that leave the emissive layer. The presence of such ablocking layer in a device may result in substantially higherefficiencies and/or longer lifetime as compared to a similar devicelacking a blocking layer. Also, a blocking layer may be used to confineemission to a desired region of an OLED. In some embodiments, the HBLmaterial has a lower HOMO (further from the vacuum level) and/or highertriplet energy than the emitter closest to the HBL interface. In someembodiments, the HBL material has a lower HOMO (further from the vacuumlevel) and/or higher triplet energy than one or more of the hostsclosest to the HBL interface.

In one aspect, compound used in HBL contains the same molecule or thesame functional groups used as host described above.

In another aspect, compound used in HBL contains at least one of thefollowing groups in the molecule:

wherein k is an integer from 1 to 20; L¹⁰¹ is another ligand, k′ is aninteger from 1 to 3.

g) ETL:

Electron transport layer (ETL) may include a material capable oftransporting electrons. Electron transport layer may be intrinsic(undoped), or doped. Doping may be used to enhance conductivity.Examples of the ETL material are not particularly limited, and any metalcomplexes or organic compounds may be used as long as they are typicallyused to transport electrons.

In one aspect, compound used in ETL contains at least one of thefollowing groups in the molecule:

wherein R¹⁰¹ is selected from the group consisting of hydrogen,deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl,arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl,heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acids, ether,ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, andcombinations thereof, when it is aryl or heteroaryl, it has the similardefinition as Ar's mentioned above. Ar¹ to Ar³ has the similardefinition as Ar's mentioned above, k is an integer from 1 to 20. X¹⁰¹to X¹⁰⁸ is selected from C (including CH) or N.

In another aspect, the metal complexes used in ETL contains, but notlimit to the following general formula:

wherein (O—N) or (N—N) is a bidentate ligand, having metal coordinatedto atoms O, N or N, N; L¹⁰¹ is another ligand; k′ is an integer valuefrom 1 to the maximum number of ligands that may be attached to themetal.

Non-limiting examples of the ETL materials that may be used in an OLEDin combination with materials disclosed herein are exemplified belowtogether with references that disclose those materials: CN103508940,EP01602648, EP01734038, EP01956007, JP2004-022334, JP2005149918,JP2005-268199, KR0117693, KR20130108183, US20040036077, US20070104977,US2007018155, US20090101870, US20090115316, US20090140637,US20090179554, US2009218940, US2010108990, US2011156017, US2011210320,US2012193612, US2012214993, US2014014925, US2014014927, US20140284580,U.S. Pat. Nos. 6,656,612, 8,415,031, WO2003060956, WO2007111263,WO2009148269, WO2010067894, WO2010072300, WO2011074770, WO2011105373,WO2013079217, WO2013145667, WO2013180376, WO2014104499, WO2014104535,

h) Charge generation layer (CGL)

In tandem or stacked OLEDs, the CGL plays an essential role in theperformance, which is composed of an n-doped layer and a p-doped layerfor injection of electrons and holes, respectively. Electrons and holesare supplied from the CGL and electrodes. The consumed electrons andholes in the CGL are refilled by the electrons and holes injected fromthe cathode and anode, respectively; then, the bipolar currents reach asteady state gradually. Typical CGL materials include n and pconductivity dopants used in the transport layers.

In any above-mentioned compounds used in each layer of the OLED device,the hydrogen atoms can be partially or fully deuterated. Thus, anyspecifically listed substituent, such as, without limitation, methyl,phenyl, pyridyl, etc. may be undeuterated, partially deuterated, andfully deuterated versions thereof. Similarly, classes of substituentssuch as, without limitation, alkyl, aryl, cycloalkyl, heteroaryl, etc.also may be undeuterated, partially deuterated, and fully deuteratedversions thereof.

It is understood that the various embodiments described herein are byway of example only and are not intended to limit the scope of theinvention. For example, many of the materials and structures describedherein may be substituted with other materials and structures withoutdeviating from the spirit of the invention. The present invention asclaimed may therefore include variations from the particular examplesand preferred embodiments described herein, as will be apparent to oneof skill in the art. It is understood that various theories as to whythe invention works are not intended to be limiting.

E. Experimental Section Synthesis of Some Representative Compounds ofthe Present Disclosure

Step 1: A 500 ml round bottom flask was charged with5-bromo-2-iodopyridine (20.0 g, 68.3 mmol, 1 eq, RI 20182-2),(3-hydroxyphenyl) boronic acid (9.5 g, 67.5 mmol, 0.988 eq, RI 20182-1),dioxane (171 ml), aq. K₂CO₃ solution (2.0 M, 85 ml, 171 mmol), andsparged with nitrogen for 10 minutes. Then added Pd (Ph₃P)₄ (4.03 g,3.42 mmol, 0.05 eq), sparged with nitrogen for 5 minutes and stirred at100° C. (a preheated oil bath temperature) for 19 h. The reaction wasmonitored by LC-MS and TLC in ethyl acetate: heptanes (1:4) and showedcompletion. The reaction mixture was cooled to room temperature, dilutedwith saturated aq. NH₄Cl solution (200 ml), ethyl acetate (200 ml),added Celite (˜12 g) and stirred for 30 minutes. It was filtered througha Celite plug, washing with ethyl acetate (100 ml), separated theorganic layer and the aq. layer was extracted with ethyl acetate (3×200ml). Combined organic layer was dried over Na₂SO₄, filtered through aCelite plug and the solvent was removed under the reduced pressure togive a brown residue (25 g) of the crude compound. Purified on a silicagel plug (625 g, 5.5″w×3.25″h) eluting with heptanes, followed by ethylacetate: heptanes. The appropriate fractions were combined,concentrated, and triturated with heptanes to give 13.1 g (77%) of(3-(5-bromopyridin-2-yl) phenol.

Step 2: To a 2.0 l three neck round bottom flask was added(3-(5-bromopyridin-2-yl) phenol (50.0 g, 194 mmol, 1 eq),(2,6-dichlorophenyl) boronic acid (212 g, 1077 mmol, 5.555 eq),Tetrahydrofuran (970 ml), K₂CO₃ (2.0 M, 436 ml, 873 mmol), and spargedwith nitrogen for 15 minutes. Then added Pd(dppf)Cl₂ (11.58 g, 15.03mmol, 0.0775 eq), sparged with nitrogen for 5 minutes and stirred usingan overhead stirrer and heated using an oil bath (internal temp.60-61.6° C.) for 20 h. The reaction was monitored by LC-MS. The reactionmixture was cooled to room temperature, diluted with 10% brine (200 ml),ethyl acetate (250 ml), added Celite (˜50 g) and stirred for 30 minutes.This was filtered through a Celite plug, washing with ethyl acetate(3×150 ml), separated the organic layer and the aq. layer was extractedwith ethyl acetate (2×150 ml). The combined organic layer was dried overNa₂SO₄, filtered through a Celite plug and the solvent was removed underthe reduced pressure to give the crude compound as a dark liquid (184.5g). It was purified on a silica gel plug (1.2 kg, 6.0″w×5.5″h). elutingwith heptanes, followed by ethyl acetate: heptanes. The appropriatefractions were combined, concentrated, and triturated with heptanes togive 50.1 g (80.5%) of (3-(5-(2,6-dichlorophenyl) pyridin-2-yl) phenol.

Step 3: A 2.0 l three neck round bottom flask was equipped with anoverhead stirrer, charged with 2-(3-bromophenyl)pyridine (37.0 g, 155mmol, 1 eq.), copper iodide (29.6 g, 155 mmol, 1 eq),(3-(5-(2,6-dichlorophenyl) pyridin-2-yl)phenol (51.1 g, 162 mmol, 1.043eq.), picolinic acid (38.5 g, 310 mmol, 2.0 eq) in anhydrous DMSO (774ml, Sigma-Aldrich, 99%, lot: SHBJ3279), and sparged with nitrogen for 20minutes. Then added K₃PO₄ (84 g, 387 mmol) and sparged with nitrogen for20 minutes. Then stirred with heating in an oil bath temperature(internal temp. 117° C.-129° C.) for 45 h. The reaction was monitored byLC-MS. The reaction mixture was cooled to room temperature, diluted withethyl acetate (1.0 l), added Celite (˜45 g) and stirred for 30 minutes.This was filtered through a Celite plug, washing with ethyl acetate(5×250 ml), the combined filtrates were washed with 10% brine (3×500ml), separated the organic layer, and the aq. layer was extracted withethyl acetate (3×500 ml), and washed with brine. The combined organiclayer was dried over MgSO₄, filtered, and the solvent was removed underthe reduced pressure to give the crude compound as a dark brown liquid(87 g). This was combined with 9 g of the crude compound to give a total96 g of the crude compound. This was purified on a silica gel plug (765g, 5.25″w×4.5″h), eluting with heptanes, followed by dichloromethane,10% ethyl acetate: heptanes and ethyl acetate. The appropriate fractionswere combined, concentrated, to give 90 g of a partially purifiedcompound. This was purified on a silica gel column (1.5 kg, 4″w×14.5″h),eluting with 2.5%-20% ethyl acetate/heptanes, the pure fractions gave11.55 g of the desired compound with LC-MS purity 99.57%. The impurefractions gave 61 g, that was purified on a silica gel column (1.5 kg,4″w×14.5″h), eluting with 5%-30% ethyl acetate/heptanes. The purefractions gave 19.4 g of desired compound with HPLC purity 99.66%. Theless pure fractions gave 10.8 g, that was purified on a silica gelcolumn (800 g, 3″w×15″h) eluting with 5%-50% ethyl acetate/heptanes. Thepure fractions gave 2.54 g of the desired compound with HPLC purity99.6%. All the fractions were checked on TLC in ethyl acetate/heptanes(1/4) Rf=0.24. These three batches of pure compound were dissolved inether (100 ml), the solvent was removed under the reduced pressure,added acetonitrile (2×100 ml), the solvent was again removed under thereduced pressure. The residue was then treated with ether (2×100 ml),the solvent was removed, then finally treated the residue with heptanes(3×100 ml), the solvent was removed under the reduced pressure and thesolid dried using vacuum pump to give an off-white gum, 30.79 g (42.4%),with HPLC purity 99.73%. ¹H NMR and LC-MS data conform to the structureof5-(2,6-dichlorophenyl)-2-[3-(3-pyridin-2-yl)-phenoxy)-phenyl]-pyridine.

Step 4: The ligand was synthesized by Suzuki coupling between thedichloride from step 3 and (3-methyl-{1,1′-biphenyl]-4-yl) boronic acid.

Platinum(II) complex of5-(4′,6′″-dimethyl-[1,1′:3′,1″:3″,1′″:3′″,1″″-quinquephenyl]-2″-yl)-2-(3-(3- (pyridin-2-yl)phenoxy)phenyl)pyridine:5-(4′,6′″-Dimethyl-[1,1′:3′,1″:3″,1′″:3′″,1″″-quinquephenyl]-2″-yl)-2-(3-(3-(pyridin-2-yl)phenoxy)phenyl)pyridine (2.93 g, 4.00 mmol, 1.00equiv), potassium tetra-chloro-platinate(II) (1.74 g, 4.20 mmol, 1.05equiv) and propionic acid (50 mL) were sequentially added to a 40 mLvial, equipped with a stirring bar and wrapped with aluminum foil. Thereaction mixture was sparged with nitrogen for 15 minutes then heated at120° C. for 70 h. After cooling to room temperature, the reactionmixture was diluted with methanol (100 mL). The suspension filtered andthe solid washed with methanol (30 mL). The solid was dissolved in DCM(250 mL), adsorbed onto Celite (20 g), and chromatographed on silica gelcolumn (250 g), eluting with 30 to 70% dichloromethane in hexanesgradient mixture. The solvent was evaporated under reduced pressure. Theresidual solid was dissolved in DCM (50 mL) and precipitated by slowaddition of methanol (250 mL). The solid was filtered and theprecipitation procedure was repeated. The solid was dried in a vacuumoven at 40° C. for 21 h to give the platinum(II) complex of5-(4′,6′″-dimethyl-[1,1′:3′,1″:3″,1′″:3′″,1″″-quinquephenyl]-2″-yl)-2-(3-(3-(pyridin-2-yl)phen-oxy)phenyl)pyridine (1.48 g, 40% yield) as a yellowsolid.

Synthesis of Comparative Compound

Step 1: A 1.0 l round bottom flask was charged with5-bromo-2-iodopyridine (30.0 g, 103 mmol, 1 eq, RI 20204-2),(3-hydroxyphenyl) boronic acid (14.25 g, 101 mmol, 0.988 eq.), dioxane(256 ml), K₂CO₃ (2.0 M, 128 ml, 256 mmol), and sparged with nitrogen for10 minutes. Then added Pd (Ph₃P)₄ (6.04 g, 5.13 mmol, 0.05 eq), spargedwith nitrogen for 10 minutes and stirred with heating in an oil bathtemperature set at 100° C. (the internal temperature was 88.5° C.) for24 h. The reaction was monitored by LC-MS and TLC in ethyl acetate:heptanes (1:4, Rf=0.26). The reaction mixture was cooled to roomtemperature, diluted with saturated aq. NH₄Cl solution (250 ml), ethylacetate (250 ml), added Celite (˜25 g) and stirred for 1 h. This wasfiltered through a Celite plug, washing with ethyl acetate (10×100 ml),separated the organic layer and the aq. layer was extracted with ethylacetate (3×200 ml). The combined organic layer was dried over Na₂SO₄,filtered through a Celite plug and the solvent was removed under thereduced pressure to give the crude compound as a brown residue (37 g).Purified on a silica gel column (900 g, 3″w×17″h), eluting withheptanes, followed by 5%-50% ethyl acetate/heptanes. The appropriatefractions were combined, concentrated under vacuum, and triturated with5% ethyl acetate/heptanes to give 22.55 g (88%) of(3-(5-bromopyridin-2-yl) phenol.

Step 2: To a 2.0 l three neck round bottom flask was added(3-(5-bromopyridin-2-yl) phenol (23.5 g, 94 mmol, 1 eq.),(2-chlorophenyl) boronic acid (75 g, 470 mmol, 5.0 eq), tetrahydrofuran(470 ml), K₂CO₃ (2.0 M, 211 ml, 423 mmol), and sparged with nitrogen for15 minutes. Then added Pd(dppf)Cl₂ (5.43 g, 7.05 mmol, 0.075 eq),sparged with nitrogen for 5 minutes and stirred using an overheadstirrer at an oil bath temperature of 70° C. for 24 h. The reaction wasmonitored by LC-MS. The reaction mixture was cooled to room temperature,diluted with 10% brine (150 ml), ethyl acetate (315 ml), added Celite(˜23 g), and stirred for 30 minutes. This was filtered through a Celiteplug, washing with ethyl acetate (3×100 ml), separated the organic layerand the aq. layer was extracted with ethyl acetate (3×200 ml). Thecombined organic layers were washed with 10% brine (150 ml), dried overNa₂SO₄, filtered through a Celite plug, and the solvent was removedunder the reduced pressure to give 87.1 g of the crude compound. Theadditional reaction set up gave 29.85 g of the crude compound. Thecombined crude compound was purified on a silica gel column (1.55 kg,4.0″w×15″h), eluting with heptanes, followed by 5%-20% ethylacetate/heptanes. The appropriate fractions were combined, concentratedunder vacuum, and triturated with 10% ethyl acetate/heptanes to give(3-(5-(2-chlorophenyl) pyridin-2-yl) phenol as a white solid, 38.9 g(91%), the structure confirmed by ¹HNMR and LC-MS.

Step 3: A 2.0 l three neck round bottom flask was equipped with a stirbar, charged with 2-(3-bromophenyl)pyridine (20.1 g, 84 mmol, 1 eq, RI20204-6), copper iodide (16.11 g, 84 mmol, 1 eq), (3-(5-(2-chlorophenyl)pyridin-2-yl)phenol (24.57 g, 84 mmol, 1.0 eq), picolinic acid (20.93 g,168 mmol, 2.0 eq), anhydrous DMSO (421 ml, Sigma-Aldrich, 99%, lot:SHBL5609), and sparged with nitrogen for 10 minutes. Then added K₃PO₄(45.6 g, 210 mmol, 2.5 eq) and sparged with nitrogen for 10 minutes.Then stirred in a preheated oil bath set at 130° C. (internal temp. 110°C.-114° C.) for 44 h. The reaction was monitored by LC-MS. The reactionmixture was cooled to room temperature, diluted with ethyl acetate (400ml), added Celite (˜15 g) and stirred for 30 minutes. This was filteredthrough a Celite plug, washing with ethyl acetate (5×150 ml). Thecombined filtrates were washed with 10% brine (3×120 ml), separated theorganic layer and the aq. layer was extracted with ethyl acetate (3×200ml), and washed with brine (2×100 ml). The combined organic layers weredried over MgSO₄, filtered, and the solvent was removed under thereduced pressure to give the crude compound as a dark brown liquid (55g). This was combined with 24 g crude compound from another set up, togive a total of 79 g of the crude compound. This was purified on asilica gel plug (800 g, 6″w×6″h), eluting with heptanes, followed by5%-20% ethyl acetate/heptanes. The appropriate fractions were combinedand concentrated under vacuum to give 63 g of a partially purifiedcompound. This was further purified on a silica gel column (815 g,3″w×16″h), eluting with heptanes, followed by dichloromethane/heptanes(1:2, 2:1), and 5%-20% ethyl acetate/heptanes. The pure fractions gave17.15 g of the desired compound with HPLC purity 99.44%. The less purefractions gave 18.5 g of the desired compound with HPLC purity 98.75%.All the fractions were checked on TLC in ethyl acetate/heptanes (1/4),Rf=0.25. These two batches of pure compound were shipped 35.5 g (46%).¹H NMR and LC-MS data conform to the structure of5-(2-chlorophenyl)-2-[3-(3-pyridin-2-yl)-phenoxy)-phenyl]-pyridine.

Step 4: The ligand was synthesized by Suzuki coupling between thechloride from step 3 and (3-methyl-{1,1′-biphenyl]-4-yl) boronic acid.

Platinum(II) complex of5-(6′-methyl-[1,1′:3′,1″-terphenyl]-2-yl)-2-(3-(3-(pyri-din-2-yl)phenoxy)phenyl)pyridine:5-(6′-Methyl-[1,1′:3′,1″-ter-phenyl]-2-yl)-2-(3-(3-(pyridin-2-yl)phenoxy)phenyl)pyridine(1.70 g, 3.00 mmol, 1.00 equiv), potassium tetrachloroplatinate(II)(1.24 g, 3.00 mmol, 1.00 equiv) and propionic acid (25 mL) weresequentially added to a 40 mL vial equipped with a stirring bar. Thereaction mixture was sparged with nitrogen for 15 minutes then heated at135° C. overnight. ¹H NMR analysis of the crude reaction mixture showeda 2.3:1 ratio of two compounds with the starting ligand fully consumed.The reaction mixture was stirred at 135° C. for an additional 6 h. ¹HNMR analysis showed a 0.9:1 ratio of two products. Heating was continuedovernight. ¹H NMR analysis indicated no further change in the ratio ofproducts while some decomposition peaks were present. After cooling toroom temperature, the reaction mixture was diluted with methanol (70mL), the suspension filtered and the solid washed with methanol (30 mL).The solid was dissolved in DCM (400 mL) and passed through a pad ofbasic alumina (100 g), eluting with 0 to 5% ethyl acetate indichloromethane. The filtrate was concentrated under reduced pressure.The solid was triturated with a mixture of DCM (75 mL) and methanol (75mL) and filtered. The solid was dried in a vacuum oven at 45° C. for 3hours to give the platinum (II) complex of5-(6′-methyl-[1,1′:3′,1″-terphenyl]-2-yl)-2-(3-(3-(pyridin-2-yl)phenoxy) phenyl) pyridine (1.13 g, 49% yield) as a yellow solid.

Device Examples

All example devices were fabricated by high vacuum (<10⁻⁷ Torr) thermalevaporation. The anode was 750 Å of indium tin oxide (ITO). The cathodeconsisted of 10 Å of Liq (8-hydroxyquinoline lithium) followed by 1,000Å of Al. All devices were encapsulated with a glass lid sealed with anepoxy resin in a nitrogen glove box (<1 ppm of H₂O and O₂) immediatelyafter fabrication with a moisture getter incorporated inside thepackage. The organic stack of the device examples consisted of,sequentially from the ITO Surface: 100 Å of HATCN as the hole injectionlayer (HIL); 400 Å of HTM as a hole transporting layer (HTL); emissivelayer (EML) with thickness 400 Å. Emissive layer containing H-host (H1):E-host (H2) in 6:4 ratio and 5% of green emitter. 350 Å of Liq(8-hydroxy quinoline lithium) doped with 35% of ETM as the ETL. Table 1shows the schematic device structure, and the chemical structures of thedevice materials are shown below.

TABLE 1 schematic device structure Layer Material Thickness [Å] AnodeITO   800 HIL HAT-CN   100 HTL HTM   400 EBL EBM   50 Green EML H1:H2:example dopant   400 HBL H2   50 ETL Liq: ETM 35%   300 EIL Liq   10Cathode Al 1,000

Upon fabrication, the devices have been measured EL, JVL and lifetestedat DC 80 mA/cm². LT97 at 9,000 nits was calculated from 80 mA/cm2 LTdata assuming acceleration factor 1.8. Device performance is shown inTable 2

TABLE 2 Device performance 1931 CIE At 10 mA/cm^(2*) At 9K nits* λ maxFWHM Voltage LE EQE PE calculated Emitter 12% x y [nm] [nm] [V] [cd/A][%] [lm/W] 97% [h]** Compound 1 0.392 0.595 540 36 0.97 1.46 1.25 1.501.04 Comparative compound 0.4 0.588 541 35 1.00 1.00 1.00 1.00 1.00

-   -   Result is normalized toward comparative example

The above data has unexpectedly showed that the Inventive Exampleexhibited lower voltage, much higher efficiencies, and longer lifetimethan the Comparative example. All these improvement numbers are aboveany value that could be attributed to experimental error and theobserved improvement is significant. Without being bound by anytheories, this improvement may attribute to the inventive bulkysubstitution which can reduce the aggregation formation and increase theoverall device performance.

1. A compound of Formula I:

wherein: M is Pt or Pd; rings A, B, C, and D are each independently 5-or 6-membered aryl or heteroaryl rings; R^(A), R^(B), R^(C), and R^(D)each independently represent zero, mono, or up to maximum allowedsubstitutions to its associated ring; Z¹, Z², Z³ and Z⁴ are eachindependently C or N; L¹, L², L³, L⁴ are each independently a directbond, BR, BRR′, NR, PR, O, S, Se, C═O, S═O, SO₂, CR′R″, SiR′R″, GeR′R″,or combinations thereof; n is 0 or 1; each of R, R′, and R″ isindependently a hydrogen or a substituent selected from the groupconsisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl,heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, germyl,boryl, selenyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl,heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile,sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; eachof R^(A), R^(B), R^(C), and R^(D) is independently a hydrogen, or asubstituent selected from the group consisting of deuterium, halogen,alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy,aryloxy, amino, silyl, germyl, boryl, selenyl, alkenyl, cycloalkenyl,heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether,ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, andcombinations thereof, with at least one of R^(A), R^(B), R^(C), andR^(D) comprising a structure of Formula II or Formula III:

X¹-X²⁴ are each independently C or N; each of R^(E)-R^(J) has the samedefinition as that of R^(A), R^(B), R^(C), or R^(D); the maximum numberof N atoms that can connect with each other is two;

Represents a single bond or a double bond; and any two adjacent R^(A),R^(B), R^(C), R^(D), R, R′, R″ substituents can be joined to form aring, with a proviso that none of rings A, B, C, and D is anN-heterocyclic carbene ligand.
 2. The compound of claim 1, wherein eachof R^(A), R^(B), R^(C), R^(D), R^(E), R^(F), R^(G), R^(H), R^(I), R^(J),R, R′, and R″ is independently a hydrogen or a substituent selected fromthe group consisting of deuterium, fluorine, alkyl, cycloalkyl,heteroalkyl, alkoxy, aryloxy, amino, silyl, boryl, alkenyl,cycloalkenyl, heteroalkenyl, aryl, heteroaryl, nitrile, isonitrile,sulfanyl, and combinations thereof.
 3. The compound of claim 1, whereinX¹-X¹³ are each C, and/or X¹⁷-X²⁴ are each C.
 4. The compound of claim1, wherein at least one of X¹-X¹³ is N, and/or at least one of X¹⁷-X²⁴is N.
 5. The compound of claim 1, wherein X¹⁴ is N, and X¹⁵ and X¹⁶ areC, or X¹⁴ and X¹⁶ are N, and X¹⁵ is C.
 6. The compound of claim 1,wherein Z¹ and Z⁴ are N, and Z² and Z³ are C, or Z¹ and Z⁴ are C, and Z²and Z³ are N.
 7. The compound of claim 1, wherein rings A, B, C, and Dare all 6-membered aromatic rings.
 8. The compound of claim 1, whereinthree of rings A, B, C, and D are 6-membered aromatic rings, and theremaining one is a 5-membered aromatic ring.
 9. The compound of claim 1,wherein two of rings A, B, C, and D are 5-membered aromatic rings, andthe remaining two are 6-membered aromatic rings.
 10. The compound ofclaim 1, wherein three of rings A, B, C, and D are 5-membered aromaticrings, and the remaining one is a pyridine.
 11. The compound of claim 1,wherein L¹, L², and L³ are each independently selected from the groupconsisting of a direct bond, NR, BR, BRR′, O, S, CR′R″, SiR′R″, andcombinations thereof, while L⁴ is not present.
 12. The compound of claim1, wherein one of R^(A) or R^(D) comprises Formula II or Formula III.13. The compound of claim 1, wherein ring A, ring B, ring C, and ring Dare each independently selected from pyridine, benzene, pyrazine,pyrimidine, triazine, pyrrole, imidazole, thiophene, furan, thiazole,pyrazole and oxazole.
 14. The compound of claim 1, wherein the compoundis selected from the group consisting of:

wherein Q¹-Q¹⁴ are each independently C or N; and the remainingvariables are the same as previously defined.
 15. The compound of claim1, wherein the compound is selected from the group consisting of:

wherein: R^(x) and R^(y) are each selected from the group consisting ofalkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, aryl, heteroaryl, andcombinations thereof; R^(E) for each occurrence is independently ahydrogen or a substituent selected from the group consisting ofdeuterium, fluorine, alkyl, cycloalkyl, heteroalkyl, alkoxy, aryloxy,amino, silyl, boryl, alkenyl, cycloalkenyl, heteroalkenyl, aryl,heteroaryl, nitrile, isonitrile, sulfanyl, and combinations thereof. 16.The compound of claim 1, wherein the compound is selected from the groupconsisting of Compound of formula T_(n-j) wherein n is an integer from 1to 116 and j is an integer from 1 to 504, wherein the structure of eachformula T_(n-j) is defined in Table 1 below: TABLE 1 Structure Z¹ to Z⁴for T₁ to T₅, the compound has wherein: the following structure forT_(1-j): Z¹ and Z² = N, Z³

and Z⁴ = C; for T_(2-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(3-j): Z¹and Z⁴ = N, Z² and Z³ = C; for T_(4-j): Z² and Z³ = N, Z¹ and Z⁴ = C;and for T_(5-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₆ to T₁₀, thecompound wherein: has the following structure for T_(6-j): Z¹ and Z² =N, Z³

and Z⁴ = C; for T_(7-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(8-j): Z¹and Z⁴ = N, Z² and Z³ = C; for T_(9-j): Z² and Z³ = N, Z¹ and Z⁴ = C;and for T_(1-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₁₁ to T₁₅, thecompound wherein: has the following structure for T_(11-j): Z¹ and Z² =N, Z³

and Z⁴ = C; For T_(12-j): Z¹ and Z³ = N, Z² and Z⁴ = C; For T_(13-j): Z¹and Z⁴ = N, Z² and Z³ = C; For T_(14-j): Z² and Z³ = N, Z¹ and Z⁴ = C;and For T_(15-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₁₆ to T₂₀, thecompound wherein: has the following structure for T_(16-j): Z¹ and Z² =N, Z³

and Z⁴ = C; for T_(17-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(18-j): Z¹and Z⁴ = N, Z² and Z³ = C; for T_(19-j): Z² and Z³ = N, Z¹ and Z⁴ = C;and for T_(20-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₂₁ to T₂₅, thecompound wherein: has the following structure for T_(21-j): Z¹ and Z² =N, Z³

and Z⁴ = C; for T_(22-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(23-j): Z¹and Z⁴ = N, Z² and Z³ = C; for T_(24-j): Z² and Z³ = N, Z¹ and Z⁴ = C;and for T_(25-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₂₆ to T₃₀, thecompound wherein: has the following structure for T_(26-j): Z¹ and Z² =N, Z³

and Z⁴ = C; for T_(27-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(28-j): Z¹and Z⁴ = N, Z² and Z³ = C; for T_(29-j): Z² and Z³ = N, Z¹ and Z⁴ = C;and for T_(30-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₃₁ to T₃₅, thecompound wherein: has the following structure for T_(31-j): Z¹ and Z² =N, Z³

and Z⁴ = C; for T_(32-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(33-j): Z¹and Z⁴ = N, Z² and Z³ = C; for T_(34-j): Z² and Z³ = N, Z¹ and Z⁴ = C;and for T_(35-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₃₆ to T₄₀, thecompound wherein: has the following structure for T_(36-j): Z¹ and Z² =N, Z³

and Z⁴ = C; for T_(37-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(38-j): Z¹and Z⁴ = N, Z² and Z³ = C; for T_(39-j): Z² and Z³ = N, Z¹ and Z⁴ = C;and for T_(40-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₄₁ to T₄₅, thecompound for T_(41-j): Z¹ and Z² = N, Z³ has the following structure andZ⁴ = C;

for T_(42-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(43-j): Z¹ and Z⁴ = N,Z² and Z³ = C; for T_(44-j): Z² and Z³ = N, Z¹ and Z⁴ = C; and forT_(45-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₄₆ to T₅₀, the compound forT_(46-j): Z¹ and Z² = N, Z³ has the following structure and Z⁴ = C;

for T_(47-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(48-j): Z¹ and Z⁴ = N,Z² and Z³ = C; and for T_(50-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₅₁to T₅₆, the compound for T_(51-j): Z¹ and Z² = N, Z³ has the followingstructure and Z⁴ = C;

for T_(52-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(53-j): Z¹ and Z⁴ = N,Z² and Z³ = C; for T_(54-j): Z² and Z³ = N, Z¹ and Z⁴ = C; and forT_(55-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₅₆ to T₆₀, the compound forT_(56-j): Z¹ and Z² = N, Z³ has the following structure and Z⁴ = C;

for T_(57-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(58-j): Z¹ and Z⁴ = N,Z² and Z³ = C; for T_(59-j): Z² and Z³ = N, Z¹ and Z⁴ = C; and forT_(60-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₆₁ to T₆₅, the compound forT_(61-j): Z¹ and Z² = N, Z³ has the following structure and Z⁴ = C;

for T_(62-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(63-j): Z¹ and Z⁴ = N,Z² and Z³ = C; for T_(64-j): Z² and Z³ = N, Z¹ and Z⁴ = C; and forT_(65-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₆₆ to T₇₀, the compound forT_(66-j): Z¹ and Z² = N, Z³ has the following structure and Z⁴ = C;

for T_(67-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(68-j): Z¹ and Z⁴ = N,Z² and Z³ = C; for T_(69-j): Z² and Z³ = N, Z¹ and Z⁴ = C; and forT_(70-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₇₁ to T₇₅, the compound forT_(71-j): Z¹ and Z² = N, Z³ has the following structure and Z⁴ = C;

for T_(72-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(73-j): Z¹ and Z⁴ = N,Z² and Z³ = C; for T_(74-j): Z² and Z³ = N, Z¹ and Z⁴ = C; and forT_(75-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₇₆ to T₈₀, the compound forT_(76-j): Z¹ and Z² = N, Z³ has the following structure and Z⁴ = C;

for T_(77-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(78-j): Z¹ and Z⁴ = N,Z² and Z³ = C; for T_(79-j): Z² and Z³ = N, Z¹ and Z⁴ = C; and forT_(80-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₈₁ to T₈₅, the compound forT_(81-j): Z¹ and Z² = N, Z³ has the following structure and Z⁴ = C;

for T_(82-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(83-j): Z¹ and Z⁴ = N,Z² and Z³ = C; for T_(84-j): Z² and Z³ = N, Z¹ and Z⁴ = C; and forT_(85-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₈₆ to T₉₀, the compound forT_(86-j): Z¹ and Z² = N, Z³ has the following structure and Z⁴ = C;

for T_(87-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(88-j): Z¹ and Z⁴ = N,Z² and Z³ = C; and for T_(89-j): Z² and Z³ = N, Z¹ and Z⁴ = C; and forT_(90-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₉₁ to T₉₅, the compound forT_(91-j): Z¹ and Z² = N, Z³ has the following structure and Z⁴ = C;

for T_(92-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(93-j): Z¹ and Z⁴ = N,Z² and Z³ = C; for T_(94-j): Z² and Z³ = N, Z¹ and Z⁴ = C; and forT_(95-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₉₆ to T₁₀₀, the compoundfor T_(96-j): Z¹ and Z² = N, Z³ has the following structure and Z⁴ = C;

for T_(97-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(98-j): Z¹ and Z⁴ = N,Z² and Z³ = C; for T_(99-j): Z² and Z³ = N, Z¹ and Z⁴ = C; and forT_(100-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₁₀₁ to T₁₀₅, the compoundfor T_(101-j): Z¹ and Z² = N, Z³ has the following structure and Z⁴ = C;

for T_(102-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(103-j): Z¹ and Z⁴ =N, Z² and Z³ = C; and for T_(104-j): Z² and Z³ = N, Z¹ and Z⁴ = C; andfor T_(105-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₁₀₆ to T₁₁₀, thecompound for T_(106-j): Z¹ and Z² = N, Z³ has the following structureand Z⁴ = C;

for T_(107-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(108-j): Z¹ and Z⁴ =N, Z² and Z³ = C; for T_(109-j): Z² and Z³ = N, Z¹ and Z⁴ = C; and forT_(110-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₁₁₁ to T₁₁₃, the compoundfor T_(111-j): Z¹ and Z³ = N, has the following structure Z⁴ = C;

for T_(112-j): Z¹ and Z⁴ = N, Z³ = C; and for T_(113-j): Z³ and Z⁴ = N,Z¹ = C; for T₁₁₄ to T₁₁₆, the compound for T_(114-j): Z¹ and Z³ = N, hasthe following structure Z⁴ = C;

for T_(115-j): Z¹ and Z⁴ = N, Z³ = C; and for T_(116-j): Z³ and Z⁴ = N,Z¹ = C; for T₁₁₇ to T₁₁₉, the compound for T_(117-j): Z¹ and Z³ = N, hasthe following structure Z⁴ = C;

for T_(118-j): Z¹ and Z⁴ = N, Z³ = C; and for T_(119-j): Z³ and Z⁴ = N,Z¹ = C; for T₁₂₀ to T₁₂₂, the compound for T_(120-j): Z¹ and Z³ = N, hasthe following structure Z⁴ = C;

for T_(121-j): Z¹ and Z⁴ = N, Z³ = C; and for T_(122-j): Z³ and Z⁴ = N,Z¹ = C; for T₁₂₃ to T₁₂₇, the compound for T_(123-j): Z¹ and Z² = N, Z³has the following structure and Z⁴ = C;

for T_(124-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(125-j): Z¹ and Z⁴ =N, Z² and Z³ = C; for T_(126-j): Z² and Z³ = N, Z¹ and Z⁴ = C; and forT_(127-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₁₂₈ to T₁₃₂, the compoundfor T_(128-j): Z¹ and Z² = N, Z³ has the following structure and Z⁴ = C;

for T_(129-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(130-j): Z¹ and Z⁴ =N, Z² and Z³ = C; for T_(131-j): Z² and Z³ = N, Z¹ and Z⁴ = C; and forT_(132-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₁₃₃ to T₁₃₇, the compoundfor T_(133-j): Z¹ and Z² = N, Z³ has the following structure and Z⁴ = C;

for T_(134-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(135-j): Z¹ and Z⁴ =N, Z² and Z³ = C; for T_(136-j): Z² and Z³ = N, Z¹ and Z⁴ = C; and forT_(137-j): Z³ and Z⁴ = N, Z¹ and Z² = C; for T₁₃₈ to T₁₄₂, the compoundfor T_(138-j): Z¹ and Z² = N, Z³ has the following structure and Z⁴ = C;

for T_(139-j): Z¹ and Z³ = N, Z² and Z⁴ = C; for T_(140-j): Z¹ and Z⁴ =N, Z² and Z³ = C; for T_(141-j): Z² and Z³ = N, Z¹ and Z⁴ = C; and forT_(142-j): Z³ and Z⁴ = N, Z¹ and Z² = C;

wherein, for each j, the substituents A, R¹, R², R³, R⁴, R⁵, R⁶, and R⁷are defined as follows: j A R¹ R² R³ R⁴ R⁵ R⁶ R⁷
 1. A1 H H H H H H H 2.A2 H H H H H H H
 3. A3 H H H H H H H
 4. A4 H H H H H H H
 5. A5 H H H H HH H
 6. A6 H H H H H H H
 7. A7 H H H H H H H
 8. A8 H H H H H H H
 9. A9 HH H H H H H
 10. A10 H H H H H H H
 11. A11 H H H H H H H
 12. A12 H H H HH H H
 13. A13 H H H H H H H
 14. A14 H H H H H H H
 15. A15 H H H H H H H16. A16 H H H H H H H
 17. A17 H H H H H H H
 18. A18 H H H H H H H 19.A19 H H H H H H H
 20. A20 H H H H H H H
 21. A21 H H H H H H H
 22. A22 HH H H H H H
 23. A23 H H H H H H H
 24. A24 H H H H H H H
 25. A25 H H H HH H H
 26. A26 H H H H H H H
 27. A27 H H H H H H H
 28. A28 H H H H H H H29. A1 Me H H H H H H
 30. A2 Me H H H H H H
 31. A3 Me H H H H H H
 32. A4Me H H H H H H
 33. A5 Me H H H H H H
 34. A6 Me H H H H H H
 35. A7 Me H HH H H H
 36. A8 Me H H H H H H
 37. A9 Me H H H H H H
 38. A10 Me H H H H HH
 39. A11 Me H H H H H H
 40. A12 Me H H H H H H
 41. A13 Me H H H H H H42. A14 Me H H H H H H
 43. A15 Me H H H H H H
 44. A16 Me H H H H H H 45.A17 Me H H H H H H
 46. A18 Me H H H H H H
 47. A19 Me H H H H H H
 48. A20Me H H H H H H
 49. A21 Me H H H H H H
 50. A22 Me H H H H H H
 51. A23 MeH H H H H H
 52. A24 Me H H H H H H
 53. A25 Me H H H H H H
 54. A26 Me H HH H H H
 55. A27 Me H H H H H H
 56. A28 Me H H H H H H
 57. A1 tert-Bu H HH H H H
 58. A2 tert-Bu H H H H H H
 59. A3 tert-Bu H H H H H H
 60. A4tert-Bu H H H H H H
 61. A5 tert-Bu H H H H H H
 62. A6 tert-Bu H H H H HH
 63. A7 tert-Bu H H H H H H
 64. A8 tert-Bu H H H H H H
 65. A9 tert-Bu HH H H H H
 66. A10 tert-Bu H H H H H H
 67. A11 tert-Bu H H H H H H 68.A12 tert-Bu H H H H H H
 69. A13 tert-Bu H H H H H H
 70. A14 tert-Bu H HH H H H
 71. A15 tert-Bu H H H H H H
 72. A16 tert-Bu H H H H H H
 73. A17tert-Bu H H H H H H
 74. A18 tert-Bu H H H H H H
 75. A19 tert-Bu H H H HH H
 76. A20 tert-Bu H H H H H H
 77. A21 tert-Bu H H H H H H
 78. A22tert-Bu H H H H H H
 79. A23 tert-Bu H H H H H H
 80. A24 tert-Bu H H H HH H
 81. A25 tert-Bu H H H H H H
 82. A26 tert-Bu H H H H H H
 83. A27tert-Bu H H H H H H
 84. A28 tert-Bu H H H H H H
 85. A1 H Me H H H H H86. A2 H Me H H H H H
 87. A3 H Me H H H H H
 88. A4 H Me H H H H H
 89. A5H Me H H H H H
 90. A6 H Me H H H H H
 91. A7 H Me H H H H H
 92. A8 H Me HH H H H
 93. A9 H Me H H H H H
 94. A10 H Me H H H H H
 95. A11 H Me H H HH H
 96. A12 H Me H H H H H
 97. A13 H Me H H H H H
 98. A14 H Me H H H H H99. A15 H Me H H H H H
 100. A16 H Me H H H H H
 101. A17 H Me H H H H H102. A18 H Me H H H H H
 103. A19 H Me H H H H H
 104. A20 H Me H H H H H105. A21 H Me H H H H H
 106. A22 H Me H H H H H
 107. A23 H Me H H H H H108. A24 H Me H H H H H
 109. A25 H Me H H H H H
 110. A26 H Me H H H H H111. A27 H Me H H H H H
 112. A28 H Me H H H H H
 113. A1 H tert-Bu H H HH H
 114. A2 H tert-Bu H H H H H
 115. A3 H tert-Bu H H H H H
 116. A4 Htert-Bu H H H H H
 117. A5 H tert-Bu H H H H H
 118. A6 H tert-Bu H H H HH
 119. A7 H tert-Bu H H H H H
 120. A8 H tert-Bu H H H H H
 121. A9 Htert-Bu H H H H H
 122. A10 H tert-Bu H H H H H
 123. A11 H tert-Bu H H HH H
 124. A12 H tert-Bu H H H H H
 125. A13 H tert-Bu H H H H H
 126. A14 Htert-Bu H H H H H
 127. A15 H tert-Bu H H H H H
 128. A16 H tert-Bu H H HH H
 129. A17 H tert-Bu H H H H H
 130. A18 H tert-Bu H H H H H
 131. A19 Htert-Bu H H H H H
 132. A20 H tert-Bu H H H H H
 133. A21 H tert-Bu H H HH H
 134. A22 H tert-Bu H H H H H
 135. A23 H tert-Bu H H H H H
 136. A24 Htert-Bu H H H H H
 137. A25 H tert-Bu H H H H H
 138. A26 H tert-Bu H H HH H
 139. A27 H tert-Bu H H H H H
 140. A28 H tert-Bu H H H H H
 141. A1 HH Me H H H H
 142. A2 H H Me H H H H
 143. A3 H H Me H H H H
 144. A4 H HMe H H H H
 145. A5 H H Me H H H H
 146. A6 H H Me H H H H
 147. A7 H H MeH H H H
 148. A8 H H Me H H H H
 149. A9 H H Me H H H H
 150. A10 H H Me HH H H
 151. A11 H H Me H H H H
 152. A12 H H Me H H H H
 153. A13 H H Me HH H H
 154. A14 H H Me H H H H
 155. A15 H H Me H H H H
 156. A16 H H Me HH H H
 157. A17 H H Me H H H H
 158. A18 H H Me H H H H
 159. A19 H H Me HH H H
 160. A20 H H Me H H H H
 161. A21 H H Me H H H H
 162. A22 H H Me HH H H
 163. A23 H H Me H H H H
 164. A24 H H Me H H H H
 165. A25 H H Me HH H H
 166. A26 H H Me H H H H
 167. A27 H H Me H H H H
 168. A28 H H Me HH H H
 169. A1 H H tert-Bu H H H H
 170. A2 H H tert-Bu H H H H
 171. A3 HH tert-Bu H H H H
 172. A4 H H tert-Bu H H H H
 173. A5 H H tert-Bu H H HH
 174. A6 H H tert-Bu H H H H
 175. A7 H H tert-Bu H H H H
 176. A8 H Htert-Bu H H H H
 177. A9 H H tert-Bu H H H H
 178. A10 H H tert-Bu H H H H179. A11 H H tert-Bu H H H H
 180. A12 H H tert-Bu H H H H
 181. A13 H Htert-Bu H H H H
 182. A14 H H tert-Bu H H H H
 183. A15 H H tert-Bu H H HH
 184. A16 H H tert-Bu H H H H
 185. A17 H H tert-Bu H H H H
 186. A18 H Htert-Bu H H H H
 187. A19 H H tert-Bu H H H H
 188. A20 H H tert-Bu H H HH
 189. A21 H H tert-Bu H H H H
 190. A22 H H tert-Bu H H H H
 191. A23 H Htert-Bu H H H H
 192. A24 H H tert-Bu H H H H
 193. A25 H H tert-Bu H H HH
 194. A26 H H tert-Bu H H H H
 195. A27 H H tert-Bu H H H H
 196. A28 H Htert-Bu H H H H
 197. A1 H H H Me H H H
 198. A2 H H H Me H H H
 199. A3 HH H Me H H H
 200. A4 H H H Me H H H
 201. A5 H H H Me H H H
 202. A6 H H HMe H H H
 203. A7 H H H Me H H H
 204. A8 H H H Me H H H
 205. A9 H H H MeH H H
 206. A10 H H H Me H H H
 207. A11 H H H Me H H H
 208. A12 H H H MeH H H
 209. A13 H H H Me H H H
 210. A14 H H H Me H H H
 211. A15 H H H MeH H H
 212. A16 H H H Me H H H
 213. A17 H H H Me H H H
 214. A18 H H H MeH H H
 215. A19 H H H Me H H H
 216. A20 H H H Me H H H
 217. A21 H H H MeH H H
 218. A22 H H H Me H H H
 219. A23 H H H Me H H H
 220. A24 H H H MeH H H
 221. A25 H H H Me H H H
 222. A26 H H H Me H H H
 223. A27 H H H MeH H H
 224. A28 H H H Me H H H
 225. A1 H H H tert-Bu H H H
 226. A2 H H Htert-Bu H H H
 227. A3 H H H tert-Bu H H H
 228. A4 H H H tert-Bu H H H229. A5 H H H tert-Bu H H H
 230. A6 H H H tert-Bu H H H
 231. A7 H H Htert-Bu H H H
 232. A8 H H H tert-Bu H H H
 233. A9 H H H tert-Bu H H H234. A10 H H H tert-Bu H H H
 235. A11 H H H tert-Bu H H H
 236. A12 H H Htert-Bu H H H
 237. A13 H H H tert-Bu H H H
 238. A14 H H H tert-Bu H H H239. A15 H H H tert-Bu H H H
 240. A16 H H H tert-Bu H H H
 241. A17 H H Htert-Bu H H H
 242. A18 H H H tert-Bu H H H
 243. A19 H H H tert-Bu H H H244. A20 H H H tert-Bu H H H
 245. A21 H H H tert-Bu H H H
 246. A22 H H Htert-Bu H H H
 247. A23 H H H tert-Bu H H H
 248. A24 H H H tert-Bu H H H249. A25 H H H tert-Bu H H H
 250. A26 H H H tert-Bu H H H
 251. A27 H H Htert-Bu H H H
 252. A28 H H H tert-Bu H H H
 253. A1 H H H H Me H H 254.A2 H H H H Me H H
 255. A3 H H H H Me H H
 256. A4 H H H H Me H H
 257. A5H H H H Me H H
 258. A6 H H H H Me H H
 259. A7 H H H H Me H H
 260. A8 H HH H Me H H
 261. A9 H H H H Me H H
 262. A10 H H H H Me H H
 263. A11 H H HH Me H H
 264. A12 H H H H Me H H
 265. A13 H H H H Me H H
 266. A14 H H HH Me H H
 267. A15 H H H H Me H H
 268. A16 H H H H Me H H
 269. A17 H H HH Me H H
 270. A18 H H H H Me H H
 271. A19 H H H H Me H H
 272. A20 H H HH Me H H
 273. A21 H H H H Me H H
 274. A22 H H H H Me H H
 275. A23 H H HH Me H H
 276. A24 H H H H Me H H
 277. A25 H H H H Me H H
 278. A26 H H HH Me H H
 279. A27 H H H H Me H H
 280. A28 H H H H Me H H
 281. A1 H H H Htert-Bu H H
 282. A2 H H H H tert-Bu H H
 283. A3 H H H H tert-Bu H H 284.A4 H H H H tert-Bu H H
 285. A5 H H H H tert-Bu H H
 286. A6 H H H Htert-Bu H H
 287. A7 H H H H tert-Bu H H
 288. A8 H H H H tert-Bu H H 289.A9 H H H H tert-Bu H H
 290. A10 H H H H tert-Bu H H
 291. A11 H H H Htert-Bu H H
 292. A12 H H H H tert-Bu H H
 293. A13 H H H H tert-Bu H H294. A14 H H H H tert-Bu H H
 295. A15 H H H H tert-Bu H H
 296. A16 H H HH tert-Bu H H
 297. A17 H H H H tert-Bu H H
 298. A18 H H H H tert-Bu H H299. A19 H H H H tert-Bu H H
 300. A20 H H H H tert-Bu H H
 301. A21 H H HH tert-Bu H H
 302. A22 H H H H tert-Bu H H
 303. A23 H H H H tert-Bu H H304. A24 H H H H tert-Bu H H
 305. A25 H H H H tert-Bu H H
 306. A26 H H HH tert-Bu H H
 307. A27 H H H H tert-Bu H H
 308. A28 H H H H tert-Bu H H309. A1 H H H H H Me H
 310. A2 H H H H H Me H
 311. A3 H H H H H Me H312. A4 H H H H H Me H
 313. A5 H H H H H Me H
 314. A6 H H H H H Me H315. A7 H H H H H Me H
 316. A8 H H H H H Me H
 317. A9 H H H H H Me H318. A10 H H H H H Me H
 319. A11 H H H H H Me H
 320. A12 H H H H H Me H321. A13 H H H H H Me H
 322. A14 H H H H H Me H
 323. A15 H H H H H Me H324. A16 H H H H H Me H
 325. A17 H H H H H Me H
 326. A18 H H H H H Me H327. A19 H H H H H Me H
 328. A20 H H H H H Me H
 329. A21 H H H H H Me H330. A22 H H H H H Me H
 331. A23 H H H H H Me H
 332. A24 H H H H H Me H333. A25 H H H H H Me H
 334. A26 H H H H H Me H
 335. A27 H H H H H Me H336. A28 H H H H H Me H
 337. A1 H H H H H tert-Bu H
 338. A2 H H H H Htert-Bu H
 339. A3 H H H H H tert-Bu H
 340. A4 H H H H H tert-Bu H 341.A5 H H H H H tert-Bu H
 342. A6 H H H H H tert-Bu H
 343. A7 H H H H Htert-Bu H
 344. A8 H H H H H tert-Bu H
 345. A9 H H H H H tert-Bu H 346.A10 H H H H H tert-Bu H
 347. A11 H H H H H tert-Bu H
 348. A12 H H H H Htert-Bu H
 349. A13 H H H H H tert-Bu H
 350. A14 H H H H H tert-Bu H 351.A15 H H H H H tert-Bu H
 352. A16 H H H H H tert-Bu H
 353. A17 H H H H Htert-Bu H
 354. A18 H H H H H tert-Bu H
 355. A19 H H H H H tert-Bu H 356.A20 H H H H H tert-Bu H
 357. A21 H H H H H tert-Bu H
 358. A22 H H H H Htert-Bu H
 359. A23 H H H H H tert-Bu H
 360. A24 H H H H H tert-Bu H 361.A25 H H H H H tert-Bu H
 362. A26 H H H H H tert-Bu H
 363. A27 H H H H Htert-Bu H
 364. A28 H H H H H tert-Bu H
 365. A1 H H H H H H Me
 366. A2 HH H H H H Me
 367. A3 H H H H H H Me
 368. A4 H H H H H H Me
 369. A5 H H HH H H Me
 370. A6 H H H H H H Me
 371. A7 H H H H H H Me
 372. A8 H H H H HH Me
 373. A9 H H H H H H Me
 374. A10 H H H H H H Me
 375. A11 H H H H H HMe
 376. A12 H H H H H H Me
 377. A13 H H H H H H Me
 378. A14 H H H H H HMe
 379. A15 H H H H H H Me
 380. A16 H H H H H H Me
 381. A17 H H H H H HMe
 382. A18 H H H H H H Me
 383. A19 H H H H H H Me
 384. A20 H H H H H HMe
 385. A21 H H H H H H Me
 386. A22 H H H H H H Me
 387. A23 H H H H H HMe
 388. A24 H H H H H H Me
 389. A25 H H H H H H Me
 390. A26 H H H H H HMe
 391. A27 H H H H H H Me
 392. A28 H H H H H H Me
 393. A1 H H H H H Htert-Bu
 394. A2 H H H H H H tert-Bu
 395. A3 H H H H H H tert-Bu
 396. A4H H H H H H tert-Bu
 397. A5 H H H H H H tert-Bu
 398. A6 H H H H H Htert-Bu
 399. A7 H H H H H H tert-Bu
 400. A8 H H H H H H tert-Bu
 401. A9H H H H H H tert-Bu
 402. A10 H H H H H H tert-Bu
 403. A11 H H H H H Htert-Bu
 404. A12 H H H H H H tert-Bu
 405. A13 H H H H H H tert-Bu 406.A14 H H H H H H tert-Bu
 407. A15 H H H H H H tert-Bu
 408. A16 H H H H HH tert-Bu
 409. A17 H H H H H H tert-Bu
 410. A18 H H H H H H tert-Bu 411.A19 H H H H H H tert-Bu
 412. A20 H H H H H H tert-Bu
 413. A21 H H H H HH tert-Bu
 414. A22 H H H H H H tert-Bu
 415. A23 H H H H H H tert-Bu 416.A24 H H H H H H tert-Bu
 417. A25 H H H H H H tert-Bu
 418. A26 H H H H HH tert-Bu
 419. A27 H H H H H H tert-Bu
 420. A28 H H H H H H tert-Bu 421.A1 —CH═CH—CH═CH— H H H H H
 422. A2 —CH═CH—CH═CH— H H H H H
 423. A3—CH═CH—CH═CH— H H H H H
 424. A4 —CH═CH—CH═CH— H H H H H
 425. A5—CH═CH—CH═CH— H H H H H
 426. A6 —CH═CH—CH═CH— H H H H H
 427. A7—CH═CH—CH═CH— H H H H H
 428. A8 —CH═CH—CH═CH— H H H H H
 429. A9—CH═CH—CH═CH— H H H H H
 430. A10 —CH═CH—CH═CH— H H H H H
 431. A11—CH═CH—CH═CH— H H H H H
 432. A12 —CH═CH—CH═CH— H H H H H
 433. A13—CH═CH—CH═CH— H H H H H
 434. A14 —CH═CH—CH═CH— H H H H H
 435. A15—CH═CH—CH═CH— H H H H H
 436. A16 —CH═CH—CH═CH— H H H H H
 437. A17—CH═CH—CH═CH— H H H H H
 438. A18 —CH═CH—CH═CH— H H H H H
 439. A19—CH═CH—CH═CH— H H H H H
 440. A20 —CH═CH—CH═CH— H H H H H
 441. A21—CH═CH—CH═CH— H H H H H
 442. A22 —CH═CH—CH═CH— H H H H H
 443. A23—CH═CH—CH═CH— H H H H H
 444. A24 —CH═CH—CH═CH— H H H H H
 445. A25—CH═CH—CH═CH— H H H H H
 446. A26 —CH═CH—CH═CH— H H H H H
 447. A27—CH═CH—CH═CH— H H H H H
 448. A28 —CH═CH—CH═CH— H H H H H
 449. A1 H H H—CH═CH—CH═CH— H H
 450. A2 H H H —CH═CH—CH═CH— H H
 451. A3 H H H—CH═CH—CH═CH— H H
 452. A4 H H H —CH═CH—CH═CH— H H
 453. A5 H H H—CH═CH—CH═CH— H H
 454. A6 H H H —CH═CH—CH═CH— H H
 455. A7 H H H—CH═CH—CH═CH— H H
 456. A8 H H H —CH═CH—CH═CH— H H
 457. A9 H H H—CH═CH—CH═CH— H H
 458. A10 H H H —CH═CH—CH═CH— H H
 459. A11 H H H—CH═CH—CH═CH— H H
 460. A12 H H H —CH═CH—CH═CH— H H
 461. A13 H H H—CH═CH—CH═CH— H H
 462. A14 H H H —CH═CH—CH═CH— H H
 463. A15 H H H—CH═CH—CH═CH— H H
 464. A16 H H H —CH═CH—CH═CH— H H
 465. A17 H H H—CH═CH—CH═CH— H H
 466. A18 H H H —CH═CH—CH═CH— H H
 467. A19 H H H—CH═CH—CH═CH— H H
 468. A20 H H H —CH═CH—CH═CH— H H
 469. A21 H H H—CH═CH—CH═CH— H H
 470. A22 H H H —CH═CH—CH═CH— H H
 471. A23 H H H—CH═CH—CH═CH— H H
 472. A24 H H H —CH═CH—CH═CH— H H
 473. A25 H H H—CH═CH—CH═CH— H H
 474. A26 H H H —CH═CH—CH═CH— H H
 475. A27 H H H—CH═CH—CH═CH— H H
 476. A28 H H H —CH═CH—CH═CH— H H
 477. A1 H H H H H—CH═CH—CH═CH—
 478. A2 H H H H H —CH═CH—CH═CH—
 479. A3 H H H H H—CH═CH—CH═CH—
 480. A4 H H H H H —CH═CH—CH═CH—
 481. A5 H H H H H—CH═CH—CH═CH—
 482. A6 H H H H H —CH═CH—CH═CH—
 483. A7 H H H H H—CH═CH—CH═CH—
 484. A8 H H H H H —CH═CH—CH═CH—
 485. A9 H H H H H—CH═CH—CH═CH—
 486. A10 H H H H H —CH═CH—CH═CH—
 487. A11 H H H H H—CH═CH—CH═CH—
 488. A12 H H H H H —CH═CH—CH═CH—
 489. A13 H H H H H—CH═CH—CH═CH—
 490. A14 H H H H H —CH═CH—CH═CH—
 491. A15 H H H H H—CH═CH—CH═CH—
 492. A16 H H H H H —CH═CH—CH═CH—
 493. A17 H H H H H—CH═CH—CH═CH—
 494. A18 H H H H H —CH═CH—CH═CH—
 495. A19 H H H H H—CH═CH—CH═CH—
 496. A20 H H H H H —CH═CH—CH═CH—
 497. A21 H H H H H—CH═CH—CH═CH—
 498. A22 H H H H H —CH═CH—CH═CH—
 499. A23 H H H H H—CH═CH—CH═CH—
 500. A24 H H H H H —CH═CH—CH═CH—
 501. A25 H H H H H—CH═CH—CH═CH—
 502. A26 H H H H H —CH═CH—CH═CH—
 503. A27 H H H H H—CH═CH—CH═CH—
 504. A28 H H H H H —CH═CH—CH═CH—

wherein A1 to A28 have the following structures:


17. An organic light emitting device (OLED) comprising: an anode; acathode; and an organic layer disposed between the anode and thecathode, wherein the organic layer comprises a compound of Formula I:

wherein: M is Pt or Pd; rings A, B, C, and D are each independently 5-or 6-membered aryl or heteroaryl rings; R^(A), R^(B), R^(C), and R^(D)each independently represent zero, mono, or up to maximum allowedsubstitutions to its associated ring; Z¹, Z², Z³ and Z⁴ are eachindependently C or N; L¹, L², L³, L⁴ are each independently a directbond, BR, BRR′, NR, PR, O, S, Se, C═O, S═O, SO₂, CR′R″, SiR′R″, GeR′R″,or combinations thereof; n is 0 or 1; each of R, R′, and R″ isindependently a hydrogen or a substituent selected from the groupconsisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl,heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, germyl,boryl, selenyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl,heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile,sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; eachof R^(A), R^(B), R^(C), and R^(D) is independently a hydrogen, or asubstituent selected from the group consisting of deuterium, halogen,alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy,aryloxy, amino, silyl, germyl, boryl, selenyl, alkenyl, cycloalkenyl,heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether,ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, andcombinations thereof, with at least one of R^(A), R^(B), R^(C), andR^(D) comprising a structure of Formula II or Formula III:

X¹-X²⁴ are each independently C or N; each of R^(E)-R^(J) has the samedefinition as that of R^(A), R^(B), R^(C), or R^(D); the maximum numberof N atoms that can connect with each other is two;

represents a single bond or a double bond; and any two adjacent R^(A),R^(B), R^(C), R^(D), R, R′, R″ substituents can be joined to form aring, with a proviso that none of rings A, B, C, and D is anN-heterocyclic carbene ligand.
 18. The OLED of claim 17, wherein theorganic layer further comprises a host, wherein host comprises at leastone chemical moiety selected from the group consisting of triphenylene,carbazole, indolocarbazole, dibenzothiphene, dibenzofuran,dibenzoselenophene, 5,9-dioxa-13b-boranaphtho[3,2,1]-dejanthracene,aza-triphenylene, aza-carbazole, aza-indolocarbazole,aza-dibenzothiophene, aza-dibenzofuran, aza-dibenzoselenophene, andaza-(5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracene).
 19. The OLED ofclaim 18, wherein the host is selected from the group consisting of:

and combinations thereof.
 20. A consumer product comprising an organiclight-emitting device (OLED) comprising: an anode; a cathode; and anorganic layer disposed between the anode and the cathode, wherein theorganic layer comprises a compound of Formula I:

wherein: M is Pt or Pd; rings A, B, C, and D are each independently 5-or 6-membered aryl or heteroaryl rings; R^(A), R^(B), R^(C), and R^(D)each independently represent zero, mono, or up to maximum allowedsubstitutions to its associated ring; Z¹, Z², Z³ and Z⁴ are eachindependently C or N; L¹, L², L³, L⁴ are each independently a directbond, BR, BRR′, NR, PR, O, S, Se, C═O, S═O, SO₂, CR′R″, SiR′R″, GeR′R″,or combinations thereof; n is 0 or 1; each of R, R′, and R″ isindependently a hydrogen or a substituent selected from the groupconsisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl,heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, germyl,boryl, selenyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl,heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile,sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; eachof R^(A), R^(B), R^(C), and R^(D) is independently a hydrogen, or asubstituent selected from the group consisting of deuterium, halogen,alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy,aryloxy, amino, silyl, germyl, boryl, selenyl, alkenyl, cycloalkenyl,heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether,ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, andcombinations thereof, with at least one of R^(A), R^(B), R^(C), andR^(D) comprising a structure of

wherein: X¹-X²⁴ are each independently C or N; each of R^(E)-R^(J) hasthe same definition as that of R^(A), R^(B), R^(C), or R^(D); themaximum number of N atoms that can connect with each other is two;

represents a single bond or a double bond; and any two adjacent R^(A),R^(B), R^(C), R^(D), R, R′, R″ substituents can be joined to form aring, with a proviso that none of rings A, B, C, and D is anN-heterocyclic carbene ligand.